Not even for streaming. But for general "safety while on the Internet" when the devices (Mac, iPhone) are mostly on public or not-so-secure WiFi (at the residence or on the go). Plan is to keep it always ON or almost always ON.
Not necessarily for the UK.
(Other than Mullvad)
though you may need to be more clear on the safety / privacy benefits you expect to gain
I've found that Mullvad generally has the best privacy reputation, but I've also been blocked by a lot of sites whilst using it.
The mainstream consumer VPNs like Nord, Proton etc aren't as great for privacy but I suspect they're less likely to be blocked. I'd love to have more data to justify this though.