Weirdly enough I'm the same, not usually into crossovers or fanfic and feel like it's sort of low-hanging fruit. That said though when I've been low on inspiration for original work I found it's pretty fun to do a few of these to tide me over until I get some new ideas again.
Plus, the kid in me that loved those franchises growing up gets a little kick out of it and it's nice giving a little nod back to days gone past.
Such an awesome surprise hearing from you man! Yeah it's pen and paper, but I clean it up digitally so it's actually black/white instead of the grey-smeared-left-kak-handed colour they usually end up as by the time I'm done. Hope you're all good, there's always time to get back on it and I'd love to see some stuff from y'all. I've only just started drawing after a year out and it's never too late to get back on the ol' wagon.