You're setting them up for a lifetime of being unable to fill out online forms (because supported characters ,minimum field lengths, &c &c always seem to be implemented poorly client side or in the DB). Some required by the government or bank or airline or police. Forcing them to go through a long manual process, if it even exists.
Then staff will make a typo in the name every time, and be locked out of their own bank account / government portal / hospital records because it doesn't match their ID. It will take months to fix each time, and half the time they will make the same mistake again, or a different one.
I go through this enough as an immigrant, and my name is 4 letters long and they are all on every keyboard. Having a name foreign to your country of residence sucks.
Also, many places have restrictions on what names they will accept. For example, I work in IT at a university. We have a fairly limited set of characters because other characters are known to cause issues with vendor products. Unfortunately, we just don't really have much of a choice.
Haha yeah. Supply chains for software are a mess (just like most supply chains), and the product with the worst character support will define the limits of everything else :(
Yup. One time we had some person try changing their name to the dragon head emoji. Some systems handled it fine, but a lot of them broke in different and interesting ways. That's what prompted the restrictions.