the fear that most users won’t run their own nodes, with the assumption that running a lightning node means a dedicated always-on server
Indeed, most users won't run a dedicated always-on server. That's not fear, that's obvious.
And consequently a fear of centralisation over time.
Breez and Phoenix are centralized, no? Non-custodial though, which is great. But do we want LN to have just 2 big nodes (ok 3, WoS too)?
user funds are secure?
User funds are secure.