Here's a sixth one: for some users it can improve latency, bandwidth and/or even cost.

latency/bandwidth: because of weird peering agreements between ISPs / ASes.

cost: there are networks where consumers pay per MB for international traffic, but not local traffic. Consumers can sometimes establish a VPN tunnel to the local data center and get an unmetered international connection, because the data center has a different agreement with the monopolistic consumer ISP.

Like, if only dissidents and malcontents use a VPN (or TOR or HTTPS or E2E encrypted messaging apps) then if you want to reduce dissent, you can just round up all the VPN users and have them shot. If everyone uses VPNs for normal internet use, that becomes impractical.

I find that using a VPN over starlink is quite a different experience than terrestrial. I can VPN through another country and the speed isn't affected nearly as much. My guess is that the route is satellite to satellite, so it is much faster.