I mean that is true but there is some nuance.

At one time it was a cheap way to protect your site from drive by scripts and make your users help pay for that protection.

They still work in that way on say the comment section of a tiny WordPress blog because the cost to solve them isn’t worth what a random boner pill ad is worth.

The issue now (made worse recently by LLMs) is that more bots then ever are scraping any and every thing so people are putting captchas on every bit of every web app content they have. This increases the work of your users while it only slows down the bots. The hope is that the cost to solve is slightly higher than the value of the data.