In the wallet, you can easily to as on-chain as cross-chain transfers. If you do it on-incognito side chain it's fully confidential.
Are there any article/example (whether non-technical/technical explanation) specific about it?
This
article explanation should be enough for you to understand
I've read that, but it's not clear whether user could send pBTC to regular BTC address as easy and fast as sending BTC to BTC address and vice versa (send BTC to pBTC adddress).
If user is required to exchange their pBTC to BTC before send it to regular BTC address manually or takes long time, then their claim (It's not a new #privacy coin, it's - a #privacy tool) is totally misleading/false.