I don't mind it. It's cheaper/easier to just pay for royalties for an existing song than to get an in-house musician, and often helps promote small time musicians to a larger audience. Or, if you take Westworld's or Black Mirror's example, helps create a sense of familiarity that is otherwise impossible with an OST.
The problem is that most of the time they're wispy hipster acoustic covers of The Smiths or something.