Why is the Character limit set to 12 on changing Gamertags?

figured as such, thank you for the answer.

Because its to allow the new gamertags to work within the old limits as NOT all games have been updates to the new system yet

So yes the limit is 12 with 3 reserved specifically for hashtags

20 characters wouldnt be accepted by games that havent been updated and some wont be if abandoned by developer

Vs 12 hashtag ones which would then be within the 15 limit therefore still work with older games without developer help

Vs adding 20 which forces all the developera to patch their games

Since it's over 12 characters, you've changed your classic gamertag, but not you regular gamertag. You'd have to change that one, but it is limited to 12 characters.

The only way to swap the names of the accounts would be to change the tag to something else and then rename then, paying each time. But you would be limited to the 12 characters when you make the change.

The 12 character limit went into place in 06/2019. It's so people can use a gamertag even if someone else is already using it. If someone else already has the tag, you would be given a suffix (# and numbers) which is why the limit was shortened. If you had
a gamertag that was over the 12 characters prior to the change, you were not made to change it, but if you change it now you cannot go back to a 15 character tag.

I want to ask, for the gamertag change, were you given a prompt like
this when changing your gamertag? Because my only guess of what it could've done is character limit since I've never seen this happen before. The character limit too is only set to 12 characters for the gamertag that'll for that says "Xbox One console and
Xbox Apps" while the second one is given a character limit of 15 characters.