A couple of thoughts on this...
I can "haul" a LOT of whatever I mine at once. And if I mined enough to fill my inventory in a single mining trip, that would be enough to last a very long time in the game. There wouldn't be any need to take a lot of trips up and down unless you're only doing very small mining trips. And if you're making tracks and a mining cart, it would take longer to place that than it would to do that few trips up and down. And don't forget that if you start out empty, you can carry enough ore in 2 trips to fully fill a *steel* storage crate and still have 10 leftover stacks of ore. Of course, you get byproduct stone in most cases as well, so that means some extra trips, but even that much would be enough of a specific ore for most players to complete their entire game. And even most of those who do a LOT of building probably don't need more than 2-3x that much for an entire game. A few quick runs up/down a mine (even half a dozen) would be faster than placing tracks and you wouldn't waste a lot of resources doing it. So it's basically just something to look nice rather than something that's actually useful.
Also, unless they also made working elevators (that would be great, btw), any mining shaft would need to be not very steep, which means you'd mostly be mining into the sides of mountains and not be able to mind downward (which is the way you normally have to mine for ore in this game) because a track can't be very steep. A normal track elevation isn't more than 15 degrees at the most, and usually less. That means you're looking at roughly 7 horizontal blocks for every 1 block down (or up).
So, although it might be interesting or "look nice", it's not really much use. Not unless there was some kind of automated mining in the game, but that isn't needed for this game.
This game isn't Factorio or Foundry or Satisfactory or similar factory games, where you have to mine a LOT of resources and get those resources to different locations. You do mine a lot of resources, but you can carry enough that transporting it isn't a problem.
And as far as travel, I don't expect many people to build track lines in the early game to get from place to place. The amount of resources would be excessive in the early game and rails can only go where they are placed. You get a bike very early in the game (usually in the first week), and that can get you anywhere instead of only on a specific path. There'd be no reason to spend all those resources to use a rail cart to travel. Now, IF there was a railroad in the game that was already placed, THEN you could make use of that to travel. But not a hand-placed rail cart track.
