It depends how you are 3 betting. You are clearly 3 betting a very strong value range. This is bad for 2 reasons (at 50nl and higher);
1. You aren't going to get paid as frequently with your nut hands. Like the situation I gave.
2. A reg like myself would target you to put you in difficult positions. You turn your hand face up so I am happy to play hands knowing I can stack you if I hit. Small PP's and suited connectors become a whole lot more valuable.
My standard is to 3bet a polarised range in position and a merged range out of position.
When I 3 bet my polarised range in position Im including most of the hands you do and then bluff hands that I cant profitably flat. A2 and K4 type hands.
When I 3 bet my merged range, mostly from the blinds against a steal, I am 3 betting hands like KQ or AT. The villain is more likely to call a 3 bet when they are in position, therefore, we are 3 betting for value, knowing that they will call with worse and taking control of the pot.
Yes, I understand your point of flatting can be better and that is why I do it when Im in position. The 3 bets are nut hands or bluffs when in position. However, when Im out of position I want control of the pot.