I don't know the age of the author, but interestingly, Gen-Z doesn't seem to use that key
There is massively different subtext between the two. Autocapitalization and autocorrect represents a limit on the subtextual bandwidth you can communicate along with a message. Restrictions on subtextual bandwith are not ideal when your generation relies on text-based communication for evermore intimate interactions - that "whats up" message might be the start of you asking someone out on a date, I don't want it formatted the same way as a message I would send my boss.
In German even ordinary nouns are capitalized, making it even less easy to find the capital at the start of a sentence.