Quote Originally Posted by Unoriginal View Post
"I have a spell for that" and "there is a portal for that", but both requires just as much DM-intervention.
Not really. A character with Plane Shift run by a player who intends to use the spell is likely to have already have tried sourcing some tuning forks, much more likely to have a 14+ int and appropriate knowledge proficencies, and almost certainly has divination spells that can help. They may be in a great position to ask the GM what their character knows, cast a few divinations, and have or already know how to get the tuning fork.

By comparison a party of people unable to cast plane shift is also much more likely to lack the intelligence modifiers, knowledge proficencies, and divinations for the basic information. That's in addition to not knowing if there's a conveniently nearby portal, not knowing how to activate it, and then fighting for or negotiating accesd to that portal.

The caster player is in a position to ask the GM a few questions, maybe cast some divinations and make a couple rolls, and (setting & GM dependent) make/buy/quest a tuning fork. The non-caster gets to ask similar questions, but then if the answer is yes (setting & GM dependent) the GM is far more likely to have to come up with the npcs, monsters, encounters, battle maps, and treasure that goes into the "find a sage to find a portal to travel to it to go through it" quest.

If the GM OKs the planar travel but doesn't like portals, is using a setting without them, or us using a setting where they aren't conveniently located, then the non-casters get a nope or the GM has a lot of work to do. Whether or not those things are true the caster has a faster, easier, and rules enabled method to do the same thing that will be less work and less intervention for the GM unless they decide to make a big involved quest out of getting the tuning fork.