You earn interest (varying) while you delegate the coins to a stake pool.

This is basically the same (details matter, ADA for example keeps the coins in the wallet all the time - AMP coins are transferred elsewhere) for all PoS (Proof of Stake) coins.

Bitcoin, on the other hand, is a PoW (Proof of Work) coin.

Edit since i can't reply downthread:

You're of course free to cash out your staking rewards however you want, but mind 2 things:

- taxes

- transfer fees

- the interest compounds..