There are two parts to this. One, yeah the optometrist wants your money, sure. You probably don’t need your script checked annually unless you’re old or there’s something serious already known to be wrong with your eyes.

But... Not perceiving a change in your vision doesn’t mean your eyes are healthy - there are all sorts of diseases that a decent optometrist is screening for during an eye exam. Most notably glaucoma, which is irreversible and often presents no symptoms. Your eyes are really really good at working around flaws in your vision, which means that you can feel like you are seeing fine when really your vision is failing. This is what a lot of “check your vision at home” things miss - they can hand you an eyeglass prescription (so long as your vision isn’t too far outside the norm) but they almost never screen for disease, and catching those diseases early can be the difference between seeing and legally blind.