Honestly I typically hate crossovers in canon, in fanworks, they can be great but that's it. Crossovers generally create shared universes/worlds, and a lot of the time, that just doesn't work or make sense for one or more of the series being crossed.
I remember it happening with two tv shows years ago both set in the same contemporary time period of the real world, one was scifi were everything no matter how crazy had advanced science as the cause behind it, the other show was urban fantasy where everything crazy was actually actual magic.
Cameos are best used like parody, good if you get it, but not important enough to derail anything if you don't.