It's not for everyone. Some people have excellent reasons why it isn't workable for them. Others have had terrible experiences. It takes a great deal of practice to be a good pair and, if you don't start by working with an experienced pair, your memories of pairing are unlikely to be fond.

However.

I paired full-time, all day, at Pivotal, for 5 years. It was incredible. Truly amazing. The only time in my career when I really thrived. I miss it badly.

I did it at a startup for a few months. The startup failed, but I think it was more of a business failure.

Pivotal Labs was a contracting firm that did it for years. They aren’t around anymore, but they had a good run:

https://en.m.wikipedia.org/wiki/Pivotal_Labs