Would've thought there'd be a bit more enthusiasm for reopening key connections on the rail network on a place like this, from the tone of the posters here I'm starting to think we're actually a petrolhead car forum and not a rail forum after all.
I'm just going to point out that in almost every case of a rural line being reopened in recent history (Okehampton, Scottish borders railway) passenger numbers and revenue have exceeded expectations. It turns out there's a lot of pent up demand from people who would prefer not to drive if given the choice, or people that don't want to sit in the miserable "freedom" of traffic that cars (and indeed buses that get caught in the same traffic) provide.
The network effect of restoring lines can't be ignored either: sure, maybe in isolation the line might not have a good economic outlook - but what about when those passengers go on to travel longer distances on other routes? Or if they can access a much better paying job and are therefore contributing more to the economy. What about sustainability? Road transport is way less environmentally sustainable than rail, and will remain so even with electric cars/buses due to the heavy emissions from manufacturing, tyre pollution and road construction/maintenance (cars are absolutely the best mode of transport when it comes to destroying their own infrastructure). I don't know if people have noticed on this forum, but we are kind of in an environmental emergency and need to seriously think about how we get more people out of cars.
Also, if they rebuilt the rest of the coastal route in the north of Wales as well, I have no doubt it would have heavy leisure travel demand - and would provide an excellent option as a secondary more direct route from North to South Wales.
Anyway, sure, maybe this link in particular wouldn't be the right thing to focus on rebuilding and there are better gains to be had through reopening other routes - but in general we should be reopening a lot more lines that were closed, or opening entirely new ones based on modern demand, both for environmental reasons and for increasing the resilience of the network (more diversion routes etc).