As I previously wrote, the WEB is full of answers for this basic question. I'm trying to save myself from pseudo-plagiarizing myself. (Besides, I type quite a bit too so I'm trying to preserve some energy ...) BUT, ya made me do it.
From The National Oak Flooring Association - Moisture Cure urethanes are harder and more moisture resistant than the other surface finishes and are generally available only in gloss. They cure by absorbing minute quantities of moisture from the air, which causes them to dry and harden. Relative humidity is critical to the curing process. Follow manufacturer's directions. These finishes are extremely difficult to apply properly and are best left to the professional. (Certainly, there may be a 'hit' of bias but it answers your question. There's more info about the other urethane(s) at the site.)
And after reading about 5 more WEB Sites that say ... MCU is extremely hard to apply and is best left to a professional, I'm done looking. In short, there's an apparent need to control the humidity. ALL these sites recommend a pro and strongly suggest that the Instructions be read and understood. IN addition, this type of finish is very good for high traffic areas (like kitchens and foyers.)
Daba-daba-daba-dat's all folks. My best to ya and hope this helps.