It does. It's high pressure. Imagine a super soaker stream right on your butthole. It's not some weak ass trickle of water like a water fountain or something
Well you can't really beat a shower after pooping, that's true. But I don't always poop just once a day, or necessarily shower every day of the week...so it'd be a pretty large waste of water/time for me to do that, personally.
If you shower after pooping, what do you do when pooping away from home? In that case, washing your butthole with water from the sink and then cleaning your hands/arms would be more efficient. You may need to loosen your butthole and expand your anal conceptions?