The last second hero balling is so overblown. It rarely happens, it's even rarer for it to be effective.
Could Lauri go off for 40 in the finals and score in the 25-30s in all the games. Absolutely I can see it. Could he score possession after possession in Kobe-type isolation. No, not right now, and doubt it will happen even with him developing.
But all you have to do is look at actual finals games. It wasn't just Giannis vs. Booker in an iso contest. Or Curry vs. Tatum. It was just as much Middleton, Holiday and even Connaughton taking shots in the final minutes of games. And CP3, Ayton and Bridges making free throws. Smart, Brown and Horford; Wiggins and even Draymond.
It's much more probable that tight playoff games come down to making FTs in clutch spots rather than that one possession with the shot clock off and trailing by 1. And there aren't a lot of #1 guys I'd rather have at the line in that situation ahead of Lauri.