As you note, being constrained in where you can go at level 1 is not a bad thing in itself, but it is a trade-off. Yes, as much as I personally don't mind it, I see how some players/designers might find such a limitation unfit for their game or not working for their playstyle.

You can still work around this without resorting to level scaling. You can give players an exploration option that avoids fighting, but sacrifices something else (ie., you can explore as a ghost, but can't take any loot with you). You can give low-level players some kind of newbie buff that will keep them alive (but won't allow them to win). You could make the perception of the world level dependent. You could also just scale locations or regions once, so that if a player reaches it at a low level, it'll become easier, and if you get there at a high level, it'll become the de facto endgame area. You could also just not implement leveling at all: The Bard's Tale (remake) was a bit like this.

Leveling up is not fun if it doesn't have an impact on how your character interacts with the world. If you're going to use level scaling to make leveling a no-op, it's often better to just go the action-adventure route and not pretend the game is an RPG. Seriously: what's the point of pumping my Strength stat if Villager A always has enough vitality to offset any gains on my part? It's especially grating if it's the same village and the same villager, revisited 40 hours later, and it still takes 3/4 of your health in a hit.

I don't think naive level scaling (Oblivion/Skyrim-style) is the right solution for "let the player go anywhere they want from the start". It's certainly a solution, but not a good one. A more nuanced mix of story justification, natural movement limitations (distance, special skills needed to get somewhere), level/area design (make areas with harder enemies less likely to be visited first), some non-combat exploration options, etc. all seem like a better way of letting the player experience open-world freedom without taking away the RPG progression "from zero to hero" from them.

I played a lot of Might and Magic VII back in the day (a few years before Morrowind IIRC). It was a huge world and you could go anywhere after getting off the tutorial island. Some endgame areas were gated behind lengthy quests, some areas were inaccessible without reaching them "the hard way" for the first time, others were impossible to reach without special skills or items, and there were skills/spells (invisibility, fly) that allowed safe passage through high-level areas if needed. Taken as a whole, it gave you a lot of options in terms of where to go at any given time, protected you to some extent from getting insta-killed because you made a wrong turn, but didn't make exploration trivial or level progression pointless. When you give players freedom, you should also allow them to commit suicide by charging at a horde of dragons while underleveled and underprepared. Trying to make the whole world immediately accessible is the kind of handholding that is actually limiting in the long run, and takes away an important part of the RPG experience. I don't think there are many CRPGs outside of TES that use level scaling - personally, I only experienced one in Wizardry 8, and it was way less absurd than Oblivion (areas had level ranges - you won't get an endgame area mob to be level 1 if you happen to reach it at that level yourself, and Villager A in starting area won't ever get to level 20 if you revisit it later).

So, between some limited/partial scaling and all the other design choices you could make, using Oblivion-like level scaling to "make the world accessible" is just bad, lazy design to me.