I trust my vets with the lives of my furbabies. When I was told that 2 of my kitties (at separate times years apart) they had it done. Cats do develope dental problems just like people. I don't feed can/wet food only dry grain free. One of my cats had a problem where her teeth bad, her littermate never had her teeth cleaned and they were sparkly white up untl the day she died at 17years old.
As for cost, it depends on where you live. In the city of Charlotte they wanted to charge me $3700 to repair my dogs torn ACL. In the town right next to me, $750. My dog had the $750 knee repair and was walking in a matter of days, back to running in 6! Never another problem in the last 6 years of her life.
If you trust your vet, have it done.