Mojang account to Microsoft account?

The Minecraft account is now changing to the Microsoft account, but what I don't understand do you have to change it or can you leave it?

In the FAQ, which you get linked in the launcher, all messages from Mojang and everywhere else, it is clearly stated that the change is mandatory and that your Mojang account will be closed completely if you refuse.

Moin, before you do anything… Don't do anything, you will get an email from Mojang explaining everything. Until then, you can continue to use your Mojang account as normal.

The change will not take place until January 2021