I'll agree with you on the fact that he's not nearly a finished product, and is a huge project.
Now.....neither he nor Bowden are proven commodities at the ML level, and with the current state of catching in the league, if you get a chance to acquire a catcher with upside, you take it, because he might wind up a 1st baseman, yes, but he may also develop into a superstar.
Isn't that the beauty of baseball?
You gotta take your chances......