It works, yes it does. But the very fact it has to be there is a problem. That airplane has the engine nacelles (for the larger, heavier LEAP engine) mounted in such a way that they will provide extra, unwanted lift when angle of attack is over 15 degrees, making the plane vulnerable to stall. The whole force/balance of the aircraft is slightly off.

Boeing put this MCAS computer compensation on that plane to make its handling characteristics "automatically" resemble that of a normal 737 model -- thus requiring no re-certification of either airplane or pilot for a new/different aircraft type.

Works fine when it works. But there are certain conditions under which it won't do its job correctly. No problem -- just throw the switch, shut down MCAS, and fly the plane by hand into a more stable situation. But first the pilot has to detect that MCAS indeed is the reason for the handling problem in order to shut it down. That can require an experienced pilot mind, coupled with some good, quick critical thinking.

OK, fine. Most old-hand professional pilots have those skills. But put an unfamiliar pilot in the position of flying this particular airplane under an adverse condition and you could be asking for trouble.