[zekica]

Trivially easy do direct connections between devices (if desired), no issues when creating VPNs between networks using private ranges.

What would be the disadvantage?

[ErroneousBosh]

Well, the disadvantage would be that it would be really difficult to do direct connections between devices.

I don't want VPNs between private ranges.

I don't want publically-routable IP addresses on anything.