 Tarastalizing will not just change your Pokemon's type in a battle, it will change the whole dynamics of battling and team building specifically in competitive play. Think about it, how many times have you been sitting there in your Pokemon builder, you've got your six Pokemon just to realize leaving some big holes in your team's synergy. Well I know this is something I've definitely had issues with in the past, but Tarastalizing can not only benefit you on a defensive and attacking level but also with your overall team synergy as well. Now just put yourself in this predicament where you've got your six Pokemon but you think oh I haven't got a ground type, I haven't got an electric resist or something along those lines. But with Tarastalization you now have technically six additional slots to pick from to put into your team. The impact and the coverage that Tarastalizing gives Pokemon team building is actually unlimited so team building feels like it's going to be so much more multi-led going forward in competitive play.