Doing it can be a pain if the cattle are on pasture, but we used it all the time when I was back home on the dairy farm. It gives a chance to be more selective about breeding and keeps diversity.
If they don't settle it is a waste of time and money, but if they stick then you could end up with better offspring. Just like any selective breeding. We only used a bull for clean up. I think a lot has changed about farming over the years I have been off that farm. Our family farm no longer exists, so that is a big change. We had a register Holstein herd with about a handful of grades and one Ayrshire who thought she was a Holstein and gave about 60-pounds a day in milk, her name was Fifi. LOL
We usually didn't keep bulls around for long because by about 2-years they would start getting to be too much to handle and it was a safety issue for us. For our farm AI was easier, especially when my brothers were all able to do it and we just bought the semen.
LOL imagine explaining artificial insemination to people who had never even seen a cow except on TV? I played out that scenario more than once while I was in the Navy. Now, I see stuff about people doing it on chickens all the time. I do draw the line there.