aight fellas, if you gotta clean out your bum, just buy a douche bulb.
having strong jets of water may fill up your rectum real quick, but 1. it's hard to control how much water is being used, 2. the pressure may damage your insides, and 3. you're also introducing air into you which will just cause a bloated feeling and farts.
your rectum doesn't have much volume, so being able to control how much water you use ensures less water goes up your intestines and therefore less discomfort and oopsie dookies on daddy's dick.
The problem isn't even how much water comes from there (you can figure it out and not set the water jet to full power), but rather that you are expected to insert this thing back and forth, which, trust me, you won't do since your anus is unprepared, unexpanded and, well, dirty.
So, while interesting on paper, this thing doesn't really work the way it's intended to. There you have it!
Quick reminder for me to search this one porn video I’ve found years ago where the woman uses this exact thing and post it here
Edit: found it! It took me waaay longer than I thought it would. That happens to "similar videos" you watch because you’re curious and then turn them off but it somehow permanently exists in your memories for free lol