I don’t know enough about the effects of steroids to be really competent to answer, but if it’s about strength, I don’t know how they would help snooker or dart players. Snooker players rarely really need strength, only when they have to play a shot with much effect, which doesn’t happen often. Snooker is more about precision than strength, just like darts.
Agreed; even the ‘powerful’ shots in snooker are much more about good technique than strength.
I don’t think it’s ever been clear how much steroids are as an active, game time PED. Certainly they help build muscle, not in the middle of a game though. And more muscle is not a necessity for all sports, and as noted a few times already, extra muscle can be a hindrance. I believe consumption of steroids does provide some increase in testosterone levels for a while, and that in itself would be helpful in many competitive situations.
Also, in any sport where the participants are tested for PEDs, having identifiable levels of steroids in your bloodstream or any other way in which they would be detected will turn into a huge competitive disadvantage after those participants are disqualified.
Is there any sport in which taking steroids does not provide any competitive advantage?
I’d say all of them, in that developing liver tumors does not help one’s competitive advantage in any sport.