You'd better believe it! It's a convention which works well when it comes up.
You can only use it over 1NT or 2NT(20-21). Responder must have a void or singleton club. It can only be used with simple Stayman.
Here is an example: Partner opens 1NT and you hold : S 8643 H 9873 D K632 C 4. You respond 2C and now pass whatever partner bids (2D, 2H or 2S). With your hand and partner's well defined 1NT bid, playing in any of these two level contracts has to be better than partner playing 1NT.
Exactly the same would occur if partner opens 2NT. In both situations you know that no trumps would be a disaster.
There's a story about a husband thinking they were playing Extended Stayman and bids 3C over his wife's 2C response to his 1NT opening. At the end of the hand after he went down three in 3NT his wife said to him "Okay, I'm sick of taking out the garbage. You can do it from now on."