It also offers more complex setups. So when I was doing interviewing I could set up a single link for a particular kind of interview. It would offer people slots where both of the interviewers were available and then have the interviewee answer specific questions up front (e.g., their preferred programming language to do the interview in).

But I mainly use it for, "Yes, let's talk, just click this link and pick the time slot that suits you."

It’s called appointment schedule/slots.

https://support.google.com/calendar/answer/11608416

I love calendly because: 1) it checks my calendar for conflicts with a link or suggest times in gmail 2) adds zoom meeting details automatically 3) avoids having to do timezone math

I just send my calendly link and don’t have to discuss back and forth about who’s available when savings tonnes of time.

but it's not very featureful.