Yeah, the most important thing is taht you can switch whenever you want, which is an unbelievably fun and cool way to play, and yes, it adds a new mindgame element, it was so funny yesterday because i just incorpored that into my game, and they didnt konw if run away or charge a smash attack, and in the end they just prefered to run away, this doesnt mean you gotta everytime you switch, because upBs are punishable moves, but certainly you can get very unpredictable with it. its very usefull, because charizards fly has superarmor and can kill(althoug doing it this way is like doing it out of shield, so it wont kill very often and is punishable if missed), squirtles waterfalll is kinda the best, because it does good damage, covers very well the area in front of him and is not very punishable when angled forward, ivys vinewhip is not very good, because used that way it wont sweetspot, so the damage and nockback wont be great, the good stuff is that it does what it has to do(cover the area in front of you) nad is the less laggy upB of the three.
I dont know if this is aplicable to other moves, but there are some that anyway wont be a good choice because of their startup lag(charizards fsmash,rocksmash, ivys usmash...) but there are some attacks taht would sound great to perform out of a change,like ivys Dsmash(quick, long range and covers both sides), bullet seed(that would be perfect!!!!!) or zards Usmash, between others.... ill try to teste it today