Some trails are worth going out of your way to ride, but most are unexceptional. For many, the only advantages are getting away from motor vehicles, and it being easier to find a place to relieve yourself. For example, I'd go out of my way to ride the Elroy-Sparta because it's a nice trail and the tunnels are cool. Or most of the GAP/C&O for the views and historic sites.
Yeah, that makes sense. Not generally found that sort of trails on my routes. I have had a lot of bike paths though. About as often as not I actually preferred to avoid them. There were some really nice exceptions though.
The Virginia Creeper trail is one that folks might go out of their way to ride because it is pretty, but I left it to ride on a parallel road to avoid the hoards of oblivious folks on rental bikes going the opposite direction. Had I been going the same way as the rental traffic it might have been okay.
I see remarkably few journals on the ECG. I suspect that people discount it once they look into it. Personally, I'd like a route that stayed closer to the ocean and bays, and have charted out one that made extensive use of ferries.
Probably true that most discount it after looking in to it. Wrt a route that hugs the coast... I suspect that a lot of the coast really doesn't lend itself well to that. After living on the east coast for 64 years before moving to the gulf coast the east coast doesn't hold much appeal for me as a touring destination.