Yes, I think so, too - I think you should have statistics at least for the website ;-).
And this is definitely no problem for users with some experience, but might confuse users who
are new
use german variant
use both app and website
So I agree - it is not an important topic, but might be a low hanging fruit to harmonize.
I can not estimate that, and people having no idea about a topic (as me in this case) tend to underestimate the effort …