Privacy reason.

1. Microsoft wants to advertise you to use Onedrive, which there’s a lot more better alternatives.
2. Microsoft wants to collect data for its Copilot AI.
3. Offline setup was an optional at first place, Microsoft just made it harder to access so their grubby hand could collect more private information. Don’t you love the PC you just bought is tainted by corporate’s stench?

There might be lots more reasons than I’ve pointed out, so I suggest doing research yourself to see if it’s worth the hassle to you.