When I first started using digital cameras, I was dismayed by the lack of a small but worthwhile accessory that I'd always used with film SLRs — a real eyecup. Quite a few manufacturers call their slip-on eyeguards "eyecups," but they aren't. They're don't keep (distracting and annoying) stray light out of the viewfinder. When I used Canon DSLRs, I went through the considerable pain of making my own eyecups — I'd found a small supply of ancient "A" series eyecups that fit nicely onto Canon's slip-on eyeguards. It was worth the trouble. (Later, the people at Hoodman finally got a clue and started making real eyecups for Canon cameras.) When I went to a Nikon system, I was grateful that Nikon continues to make real eyecups for its higher-end DSLRs. I was bummed to find that Fuji doesn't.
But never say die. Again I've made my own using the stock X-T1 eyepieces, Nikon rubber eyecups, and the great adhesive product called Sugru — and as with the Canon cameras I'm glad I went to the trouble. (I wish I could buy not just the extended eyecup for the X-T1, but also the smaller one that comes with the camera — it's easier to work with.)
But is this DIY business necessary? Does any third party make a real (round) rubber eyecup for the X-T1, attached to a proper-fitting slip-on eyepiece? I asked Hoodman about this, but they claimed in their reply that it costs about $100,000 to tool up for a new product — and they don't think the Fujifilm cameras are a big enough deal to make such a product worth their while. Maybe it isn't worth their while, but I would still think there's a market for a small but sometimes pretty important accessory like that.