No doubt nostalgia plays a role in how much it's revered, similar to how Gopher fans feel about the Barn. Also it just sounds fantastic. It's always been great, but their recent updates have made it even better.
Additionally, the musicians themselves hold the venue in such high esteem, I am convinced it leads better performances. They appreciate the nostalgia as much as the fans, are treated well by the staff by all accounts and know how great it sounds. It usually ranks at or near the top when I have seen national polls for clubs of it's size by artists.
Case in point, Spoon had to cancel their first of 2 shows last week at the Palace in St Paul due to the singer Britt Daniel falling ill (must have not been COVID). They jumped at the chance to make up the gig at 1st Ave on Sunday, driving all the way back from Milwaukee after their Saturday performance. The band's comments show just how much they love the place.
The Texas rockers' switch to the club from the Palace Theatre coincided with them getting a star on the wall.
I'm just a casual fan of Spoon, but had a I known beforehand I would have tried to go. They put on a good set when I saw them at Ohana Fest this past fall.