Mmm.
I thought the event was good, if a little ... lacking, in terms of impact for the end? I mean this was more or less a feel good, what if story, at least the way it had been presented in the game (we will see how it all plays out in the novel(s)).
I guess the end point is that Nasu really wanted to see Roman and Moriarty interact with each other, so even if the entire thing doesn't really fit in any particular point in the timeline (and is pretty much an impossible scenario, given the way things played out in the story) it still is a story that is worth telling. At least from the author's perspective.
I wouldn't deny it was nice seeing Roman again, and even if it creates a plot hole or the whole event is non-canon, it was also kinda cool seeing him interact with the part 1.5 and 2 servants.
It does sort of make this event less memorable when compared with Kogetsukan, since it's pretty much like a What-If issue rather than something that adds to the current story. The meta commentary was cool and all, meeting the shichibukai was dope, and I do get that its about the central conflict that the Lostbelt's is about, but I guess I wanted for there to be more of a mystery, more significant to have occurred in the actual event story itself. Kinda like how White Day '19 went with its story.
Still liked it a fair bit, hope they do continue with making events like these. Just, I hope that the voting isn't arranged like this time where one character ends up eating half the votes.