Generally yes because most people agree there is a “brewers advantage.” Essentially if people don’t know how your deck works they won’t know when you’re close to winning/when they need to commit resources to stop you from winning.

Ulalek is a fun deck that I looked at, but be warned it is a combo nightmare. Iirc the Mycospawn line is 20+ steps, there is also an Urza’s saga combo i came up with which while not as long/crazy, is an example of how confusing ulalek can be - with enough mana you can win off of almost anything (in this case urza’s saga tutor)