If you are trying to avoid your ISP knowing you are downloading movies a VPN is a good solution.
If you don't want others in the coffeeshop to be able to snoop on remaining unencrypted http traffic. VPN
If you don't want your employer to have a list of your web traffic from your personal device. VPN
If you don't want a service which you don't pay with a credit card to have a way to connect your pseudonym to your real name. VPN
If you want to opt out of some degree of dragnet surveillance/data collection via parties like your ISP. VPN
None of these are incredibly uncommon. VPSs work great for most scenarios. If your actions are dangerous to your continued existence or you need to keep your own government from watching you then you probably need to adopt far more stringent measures but I feel this is vastly less common than the above situations.
If you're worried about a government, your personal info from a VPS provider is just one court order away. If you use a VPN service that actually is serious about not keeping PII or logs, you might fare better there (they might be coerced to log future traffic of yours, but at least your prior activity is still secret).
If you're worried about ad tracking, a VPN just doesn't do you much good period: ad tracking is sophisticated enough to not care about your IP address.
But all of this "VPN for privacy" stuff is predicated on trusting faceless third-parties to help keep you safe, so it's generally a losing proposition. Agree that the only "safe" thing to use a commercial VPN for is to bypass geographical restrictions.