I would say a little of both. It's one of the reasons that I love Dark Souls so much. Yeah you've got a linear path to follow, and such, but there is a lot to see.
Open world games used to amaze me back when GTA3 came out, but now other than a few places that stand out in open world games, it's more or less the same street/valley/field copy pasted ad nauseum.
Plus it's much easier to make great looking levels when a player is "railroaded" through it.
Besides, when I played Oblivion and Skyrim, I tended to fast travel when possible, because there isn't really much to see anyways (unless it's a PoI on the map, and even than most were just smaller waypoints.) Not saying there weren't some cool setpieces in Skyrim and other open world games, but it felt detached from the rest of the games world, whereas Dark Souls' World felt like one big setpiece. Demon's Souls felt detached too, but I think that's mainly due to how the Nexus handled the traveling.
It's another reason why I hold Super Metroid(2D), and Dark Souls(3D) up as high as I do in level design. Zebes was roughly an open world(in fact all Metroid games have been, I think), but you were pulled through it in a semi-linear fashion. You could sequence break, and there was a lot of exploring to do. You could beat the game and come back to try to find other hidden areas and such that you didn't find last time. Hell, my last play through, I had found a room with this weird turtle thing retracting into its shell and spinning at me(It was in Maridia if you're curious). And I thought I had found everything already, or at the very least, seen every creature on the planet.