If you are male (especially) and wear neck entry or zip shoulder catsuits, then you may find getting your bits out for a pee or whatever is a bit tricky. Very probably you will not have a zip down the front.
You can have a crotch zip, of course. We don’t like them. They are not stretchy and uncomfortable to wear, catch when you use them and spoil the line.
A codpiece is far better. It’s more comfortable to wear (in our opinion), emphasises your assets and you can experiment with different colour combinations.
You can get a catsuit with a cock hole. These are great but wearing them in public is a bit tricky.