It’s relevant to whether or not his death deserves the label “plot hole” that you were slinging around earlier. I agree it’s not relevant to the other reasons you disliked his death.
You see him as a mystery that needed explaining. I see him as a set of visual signifiers of EEEVIL which hadn’t yet been backed up by anything interesting (cf. Darth Maul). Most blockbuster movies these days fail to make their villains interesting, and as I said, I didn’t have particularly high expectations for Snoke on this front.
On consideration, I’m happy to concede that they could conceivably have found something to do with Snoke’s story that made him interesting (against what I too loosely said above, that Snoke would never have been as interesting as Palpatine). They had a couple of movies to work with. If they’d managed it, that would also have been fine by me.
But by killing him they took Kylo in a much more interesting direction than he’d been headed in (and Kylo was already much the more interesting of the two, just as Vader was always a more interesting character than Palpatine). Snoke’s death opens up the heady possibility of Kylo and Rey walking away from the Jedi-Sith dichotomy, which ultimately doesn’t happen because Kylo remains who he is – with his character revealed so much more clearly when he’s the one calling the shots. All of that stuff could only happen with Snoke dying. They’re what made his surprisingly early death more interesting than e.g. Darth Maul’s, and why I disagree that it’s merely subversion for subversion’s sake.
As a decades-long GoT fan, I don’t think the unceremonious killing-off of powerful characters (including e.g. the Book One protagonist) is a bad thing. If the TLJ team had decided to kill off Rey, or Rose, or Finn, I’d have judged the effectiveness of that unexpected choice by the impact it had on the other characters/plot. I’m satisfied with Snoke’s story ultimately being an aspect of Kylo’s. I don’t need to know his backstory, any more than I need to know a dozen other worldbuilding details.