My issue is that I have enough of a bit of a tummy, particularly when bloated, and not enough of a bum for trousers to not stay up without some sort of a belt, which doesn't work with either a side or rear zip. Then again, my bit of a tummy includes a fair bit of loose skin, which shows through anything smooth at the front. Bulky clutter like zips and pockets covers it all up, nicely.