A PhD -- especially in CS -- is not really best understood as "furthering your education" in the traditional sense. It's better understood as a paid apprenticeship in R&D.
It's preparation to become either a professor at a university or an independent researcher at an industrial/government research lab. It won't increase your lifetime earnings or job prospects, but it does open up doors to jobs whose primary allure is intellectual freedom rather than material reward.
If you don't go one of those two routes after a CS PhD, then a CS PhD has rather high negative expected value except in a few special circumstances (e.g., BS from NoName Branch Cappus to PhD from mit/cmu/stanford. But that's not the typical case for non-immigrants.)
It's preparation to become either a professor at a university or an independent researcher at an industrial/government research lab. It won't increase your lifetime earnings or job prospects, but it does open up doors to jobs whose primary allure is intellectual freedom rather than material reward.
If you don't go one of those two routes after a CS PhD, then a CS PhD has rather high negative expected value except in a few special circumstances (e.g., BS from NoName Branch Cappus to PhD from mit/cmu/stanford. But that's not the typical case for non-immigrants.)