I use a mixture of roads and cycle paths “now” as they are suitable for my needs. When I lived in Lincs the laughable one at the side of the A607 on the way to Waddington was in disrepair and too narrow for a shared path, so I rode on the road.
The only issue I have with 2 of the wider cycle paths by me is that they come down a hill and it’s easy to get up speed (on the road you’re doing 35mph with little effort) and even though it is very wide and has a distinct separator down it, you get folk bimbling on the cycle part (usually with about 8000 dogs on those extender leads). I know there’s nothing to stop them, however this is why most serious cyclists won’t use cycle paths as pedestrian dodging at speed isn’t fun.
One of the Sustrans paths near me is in a great location, but the path is a battered farm track so isn’t suitable for road bikes so roadies won’t use it.
Also don’t the govt recommend you being on the road if you’re doing 17-18mph+
Right that’s enough from me 😀