Wipe-clean-only protectors are typically hard-shell designs or over-pants styles that you wear on top of your base layers. Since you can only wipe them down with a damp cloth rather than fully wash them, they're not ideal for next-to-skin wear—sweat and bacteria will build up over multiple days of skiing.
These designs work best as outer layers, where they're not in direct contact with your skin. If you prefer wearing your hip protector under your ski pants, you'll likely want a machine-washable option with removable pads instead.
That said, wipe-clean protectors do have an advantage: they're very low-maintenance and dry instantly, which can be convenient for day trips. Just keep in mind that for week-long ski vacations where you're sweating on the slopes every day, the lack of a real wash becomes a hygiene issue pretty quickly.