Hi guys, what are stable coins exactly?

Are they a good way to look in profits from the volatility of the crypto market?

Please correct me if I'm wrong as I'm trying to understand what a stable coin is.

Example, if you buy 1 alt coin for $100 and next day it's value increases 10% and now your 1 alt coin's price is $110. If you wanted to lock that profit could you move that $10 to a stable coin such as tether rather than BTC where the price appears to be fluctuating too much for my liking.

How do you transfer your money out of the altcoin and into a stable coin?

Are they any stable coins which do not require intrusive KYC details?

Do you think stable coins are the future?

Many thanks.