"Okay folks, going to find the tile and dig it open to rock so we can erupt it!" (Five hours later) "Here is the correct tile on the surface, all dug down to rock! Bring the Path of Power char, and let's erupt this tile!" (Ten minutes later) "Boo! No Mag domain. Build an altar first, please..." (Fifteen minutes later) "Oh wait, now we need to bless it. My priest does not have prem. Okay, so first we need to pay additional money to prem said priest (or hire another priest), to bless the altar, after which I can use my PoP char to erupt the tile..." (Either forks out 5 silver to prem priest if you are lucky enough to have one, or ask in GL for a priest to travel to you and then pay him to bless the altar...this could take a day, or two...) "My weekend is over, working all week so will have to wait until next weekend to erupt the tile!"
Next weekend: "Yay, got the tile erupted! Now for the second one in this tunnel..." "Oh wait, there is a deed close by with another priest domain. Think they will be happy to bash their altar so I can erupt this tile because I can only do it in a Mag domain?"
It is unfair that this is literally the ONLY meditation spell in the game which has any interaction with domains for it to work. It is also unfair that, if you don't have a premiumed Mag priest, you will have to fork out money to get a domain in an area where a MEDITATION spell is supposed to work. To make it a prerequisite means you have to mess up your current domains just for this cast.
These things make it hard. (Not to mention the 18 hour cool down, which also makes it hard.) (And the time it needed to get your char to that meditation level in the first place.)