Nice hand imo.
I do not agree you have to bet flop here. Check is fine vs 2 players. You might even give up turn to big sb lead (you only beat bluffs or fish spews, and you have 1 player behind you still to act). On the river it is the same, you beat nothing, so good fold.
Mw we bet when we have it.
We have what? Top pair, no kicker is all we have. True, some broadway combos could call, but if that were the only concern, we might as well bet this flop with 33-99.
might call as well, but they are not going to call more than 1 or 2 streets anyway, so we can still bet later streets vs them.
Would we bet this flop with KK-JJ? Our hand is effectively the same hand strength as KK...
(the only difference being that with KK-JJ we would block many broadway combos in villains´calling range, and of course there are more aces in their range as well, so I agree betting with A3 is significantly better than betting with KK, still I am not convinced that it is a compulsory cbet).