Once you buy java, you can add multiple Microsoft accounts, which all have acces to Windows edition, despite not having paid for it.

If you log in with a different microsoft account in the launcher, you can run minecraft bedrock edition, without having paid for it. You shouldnt be able to do that, as far as i know.

Steps to reproduce:

• Buy minecraft java edition

• Log in with a different account, which doesnt have paid for any edition

• Navigate to Minecraft: Bedrock edition and press “play”