In the old days, they were a separate free-standing device. Not a lot of people have space or money to add one of these types of bidets to their bathrooms
Now they make them as toilet seat attachments that don't require extra space and really aren't that expensive.
But people don't know. Older people will be like, "Oh a bidet? No I don't want another toilet like device in my bathroom"
So that gets rid of all those people.
Next you have the people that know about the new style bidets that's just a fancy toilet seat.
Their biggest deterrent is probably cold water. Spraying cold water on their butt doesn't appeal to most people.
You can get bidets that heat the water, but you have to have power behind your toilet, which not everyone has.
Then you have older people that just can't work them or don't feel like they can. Like my grandfather, I installed one with all the bells and whistles for him. Yet hitting a button and doing all that was too complicated. He was 90+ and could barely use a cell phone for basic functions. But he'd rather wipe his butt like he knew than mess with the "complicated" bidet.
Eventually everyone is going to own a bidet, it really is the way to go.
For me it's because I have had to suffer from UTI's before and I don't want to risk some stream of water blowing bacteria into my vagina and then I gotta pee every five seconds and wait for a damn doctor visit because for some fucking reason UTI meds aren't over the counter where I live.
I can buy the UTI "pain reliever" over the counter but it just temporarily fixes the pain, and the UTI of course continues. Pretty fucking pointless.
Well, for starters, you don't pee from your vagina. You could get a yeast infection, yes, but that's a different issue.
That said, if your bidet is angled so it's hitting your vagina or, especially, your urethra, it's likely not installed correctly or you're sitting way far back on your toilet.*
There are bidets you can get with the option to angle for washing period blood away, but they tell you in the instructions to wash your butt first so that you don't get bacteria into your vagina, and you also don't need to use that function either. I never found it super useful myself, so I'd recommend the cheaper version without that function these days.
Having used both types, including a water warming seat installed one, I can't say enough good things about the free standing ones. The toilet seat ones though seem like a waste of time, even if they warm the water.
If the water in your pipes is even close to 1°C you have a serious problem.
You can also hook a bidet to your hot water line
The first bit of water will be wall temperature water and it will take a bit to fully warm up because you have to clear out the lines (some bidets will drain the first bit of water before squirting you)