As a french bubble app we also use the comma as a currency separator.
I think the behavior you describe is the intended behavior for the decimal content format and that it’s an alright user experience.
I might be biased though because the azerty (french) keyboard requires you to press shift + dot key to print the dot character. Since the comma and the dot key are next to each other it would be odd for an azerty keyboard user to use the dot key instead of the comma one to input a decimal amount.
@pierre6 Thank you very much for your quick answer. I didn’t have in mind the french keyboard, as in Switzerland we have a qwertz keyboard and the “.” is the first function of the the “.” key.