Currently the app only accept periods as decimal points, but as you might know a large part of the world use commas as their decimal point.
This would normally not be a big deal since I could just use a period instead, but in this case all number inputs brings up a keyboard that only has the comma (see image).
Therefore it isn’t possible for me to for example buy a fraction of a Bitcoin (unless I do some workaround like pasting the number from outside the app).