If you want to find YOUR own answer, it is easy: test yourself...
And it does not even have to be long or expensive, 2 hours at any 100-yard range or appropriate place with a .22 LR, a brick of 50 rounds, and a few dessert paper plates (6") will do.
Since it is about oneself, I can only share my own experience, but it is enlightening... and humbling...
1) Standing off hand
At 100 yards, standing off hand, it is a very, very good day for me if I hit the 6" steel plate 50%+ of the time, and some of the misses are wild (we are talking feet, not inches), and some of the hits are pure luck.
In my own set of ethics, this is unacceptable performance for ethical hunting.
Note 1: driven wild boar on the run at 25 yards is different, and easier if you can swing, but few shots are really clean, and the 9.3x62, common in Europe for these hunts, buys you a bit of time for a quick finisher.
Note 2: I am sure many folks do a lot better, and that is fine with me.
2) Keeling with left elbow on left knee and seating on my right ankle, with the hasty sling (I am right handed)
Note: Having been trained in the French military, kneeling with one elbow rest is what I learned. Then I shot .22 LR "Three Position" for years. I understand that the US military teaches seating with both elbows rested on both knees held off the ground. I have tried. Somehow it does not feel natural to me (force of habit?), and my left knee is nowhere near as immobile off the ground in a seating position as it is a kneeling position. To each our own based on our training...
At 100 yards, kneeling, I commonly hit the 6" steel plate about 80%+ of the time, and the misses would probably ring an 8" plate (based on similar tests on 12" paper plates).
Considering that most game the size of white tailed deer have a 12" vital area, I consider it acceptable to take close-range kneeling shots on the fly on fleeting wounded game during a follow up.
3) Tripod sticks
At 100 yards, on the tripod sticks, I commonly hit the 6" steel plate about 90%+ of the time.
However, the rate drops to around 80% at 200 yards and around 75% on a good day at 300 yards.
This became my standard shooting position after I discovered the PH sticks in Africa, but I avoid tripod sticks now.
4) Quadpod sticks
At 100 yards, on the quadpod sticks, I hit the 6" steel plate virtually 100% of the time.
The rate still drops at 200 and 300 yards, but I typically stay in the 90% range, and since virtually anything one would shoot at 300 yards has a 12" to 18" vital area (remember, I shoot a 6" steel plate), I consider this acceptable.
I now bring my own quadpod sticks to Africa. Mine are the carbon fiber 4 Stable Sticks.
Notes on bipod prone...
Having gone through regimental sniper training, and having continued shooting long range steel regularly my entire life, with an accurate laser range finder, a barometer/altimeter/wind gauge (Kestrel), a BDC scope, and plenty of time, I hit the 8" steel plate close to 100% at 300 yards (ah! but the wind down range.........) and generally the 12" plate 80%+ at 500 yards.
HOWEVER, it only takes 18" low brushes to make it impossible to use a correct prone position in flat land, and I have only once had the opportunity to shoot prone in Africa (see PS1).
I have zero experience with seating height bipod. Maybe I should try. But since my quadsticks adjust effortlessly to seating height...
Note on field rests...
Leaning/crawling/wrapping oneself on a convenient 4 to 5 ft round boulder, with the day pack under the rifle forend, precision and accuracy can reach prone level. I have used this position many times in mountain hunting, in Africa and elsewhere, and I leave the sticks aside if I can achieve it.
Similarly, seating with the forend resting on a bush/small tree branch of just the right strength and at just the right height, or grabbing firmly forend and small diameter trunk, precision and accuracy can also be very high. But this is not a common situation.
So, there you have it, my own answer, for myself, based on my own shooting data, is that I do not shoot standing offhand; very rarely kneeling; do not bring a bipod to Africa, but my shooting improves enough with the quadsticks over the tripod that I bring my own to Africa just to be sure to have one set on hand.
PS1: I do not take shots off the sticks (tripod or quadpod) at more than 300 yards (just hunt closer...) and I do not take shots prone more than 400+ yards - 500 yards at the outmost, and it is a rare shot indeed: exactly one in Africa, and I only took it because the fading light made it a "take this shot or go home" only option, and nature provided me a near ideal position (well grazed plateau, perfect size rock under the forend + folded knit cap to absorb vibrations, second perfect size rock under the buttstock heel, no wind at dusk, plenty of time).
PS2: I am sure that many folks on this forum shoot better than I do, and all the power to them, but I have also seen many bruised ego during shooting sessions with friends who sincerely believed that they shot a lot better than they actually did. Apparently, self-indulging opinions are a lot easier to formulate (and a lot more forgiving) than collecting objective data... If you doubt that, Jim Harmer has some very "interesting" segments on 500 yards hunting-conditions shooting challenges on his Backfire.tv channel...