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)
But a VPN would have been more appropriate for this task and if ever I needed to use a different IP from a different country (that would be rare and mostly to access websites for a short period) I could just do it easily.
Mullvad, however, leads to Captcha City and is straight up blocked on a couple of sites, namely McGearHub and, for a time, Runescape. Btw, if you have a friend using it, you can likely mooch off their sub. I share mine with 2 other people since the device limit is 5, and I only have my phone and PC on it.
I'm guessing the captcha city situation might be better with more "casual" VPNs but I doubt it makes much of a difference once you have a bunch of people on the same IP.