Tintin in America is very early Tintin. I wanted to give an early work by Hergé a try to see what his progress was as a writer and artist. From reading this one, it is clear that Hergé improved as he went along. The plot of this one really amounts to no more than Tintin goes to America to investigate the mob. The mob get wind of this and repeatedly attempt to capture, kill or scare off Tintin. Tintin repeatedly foils these plans, mostly through lucky accident.
The merits of Herge as a writer are mostly not with the character of Tintin, who has few characteristics other than being earnest and being determined. At this point, all the interesting characterization and commentary must come from the dog Snowy, who has to do too much narrative heavy lifting as a result. There just is no real narrative arc to the whole thing, and Hergé will become a much better story teller later on. As to the art, my favorite stuff with Hergé has always been the landscapes. At this point, Hergé had not really discovered landscape and his panels where he redrew the comic strip to make something nicer are few and not that well done.
Also of note is that the book deals with various stereotypes about America. Some of the ones about Indigenous peoples are offensive, although they are not done in an offensive spirit.