For simple games for simple puzzle, adventure games for lambda user i odn't think they expect great physics and A8 system is sufficient in this case.

FPS for example games are not for really lambda people , but more for people that like FPS games and lot of time, paly today FPS games. SO in that case no problem with Physix install !

Even some AAA RPG ask to install additionnal package like Physix and others.

In fact it really depends on your game type and the type of people you target to use or not Physix.
If really casual , not core gamer, well you can avoid i'm sure
Physix caus they don't exepect accurate or incredible simulation.

Once again is all up to you to decide