Minecraft account migration?

I opened minecraft and it says that you haven't started the account transfer yet, but can I still play minecraft? I also see some people playing mc anyway (e.g. Luca)

Yes you can play
When you start the account migration, you need to convert a Mojang account to a Microsoft account.
So doesn't apply to any person who just bought Minecraft.

Sure, how else should all players play it? Minecraft will of course not shut down services in the meantime.