Used to be long flat roads, especially on the Delaware side. Delaware is building on every slot of land, carpet bombing housing developments. You now need to head 30-40 miles south to find those long, and still safe roads.

C&D canal path, where I ride most of the time, 8 min sections max.

Maryland side - 12 min sections max. Flat, but not flat. Little elevation gains, but short/punchy hills everywhere there is a creek or river off the bay. I can’t get out of my house without hitting 10-17% grades - short, but punchy. And no, I’m not staying in z2 over 10%!!

I get what Rchung is saying, but will add one thing. With ERG mode off, Zwift for example, offers all sorts of variable terrain. Terrain that mimics outdoor conditions very well - without interruptions, stop lights… every terrain possible at any time. Flat, punchy, hilly, mountain…

Not sure there is any weakness or negative there.