Are runbacks always bad?

I’ve been thinking about this a lot, and can never quite make up my mind.
Are boss runbacks always a negative thing?
In earlier souls games, there was more of an emphasis on level design, on the boss being one part of a whole gauntlet. This adds to the difficulty by forcing you to master the whole level rather than just getting through it once. But these runbacks can very easily become repetitive, especially if you take double digit attempts on a boss, especially if you’re doing a Soul Level 1 run.
Elden Ring (mostly) removed them entirely (fuck you renalla and placidusax) which was the right call considering the escalation in difficulty. If Malenia had a runback I would not have beaten her. Yet by that same reasoning, I wonder if having more runbacks would have caused the devs to focus less on absurd difficulty in the boss fights and more on refining the level design, bringing it closer to older games design-wise.

In the middle stage of souls games, Bloodborne and DS3, runbacks are in a weird limbo state where they can be quite long but they’re very rarely actually threatening. Instead a lot of them are long elevator sequences like with Dragonslayer Armor, Midir, or Mergot’s Wet Nurse. These are the worst of both worlds, long and annoying nwhile also unengaging. They serve no purpose and I just want a bonfire/lamp/stake of marika there instead.
What do y’all think? Are runbacks exclusively negative or do they serve a purpose?