I have both the CZC plate system and a direct milled slide.
Both have their upsides and downsides
CZC plate you can switch optics or use iron sights (if you buy the iron sight plate which is $80 I think).
It sits up a little higher and I don’t think it’s quite as secure as a direct mill. No matter what I tried the screws would work loose eventually. (I’m sure someone will argue otherwise but that’s been my experience). It can sometimes be hard to find the plates in stock as well, the steel is a better choice than the aluminum ones.
Direct mill is great fit, snug and low as possible. Obvious con is once you commit to an optic, that’s it, your stuck with that footprint.
Fir competition don’t worry about back up sights. Most prefer to take the front sight off too.
Personally I’m not sure I’d pick the delta point as my optic but that’s another discussion entirely.