When you still have to wipe after using a bidet it can be due to you having more sticky poop that cannot be fully cleaned off your bottom or the water stream from the bidet is not strong enough to fully wash away the poop.
The water pressure in homes can vary which can affect the water pressure in the bidet and sometimes the water pressure may not be good enough to clean your bottom fully.
Also the bidet often has a water dial which can control the water stream so the water dial may be set too low as well.
A clogged bidet nozzle can also be a cause of incomplete cleaning and require you to wipe.
Bidets are generally very safe and hygienic although they can have potential to be unsanitary and may cause issues for some people if they're not used or installed properly.
If not cleaned properly and often enough the bidet can also be gross and unsanitary.
A bidet may not always clean your bottom of all the poop and if you have really sticky poop, the light stream of water from the bidet may not get you clean very good or at all in some cases.
So you still may have to wipe after using the bidet.
However using a bidet is also considered more sanitary than wiping your bottom with toilet paper because in some cases the water may be able to wash away the poop more thoroughly and reduce the risk of bacteria transferring to your hands and other areas.
The bidet uses a stream of water to clean your bottom or perineal area, and removes poop and residue.
Toilet paper can sometimes leave behind particles.
Although if you have sticky poop it may not come off all the way and still require some toilet paper.