If I can travel with Fauji XT-1 and some XF lenses such as 35mm1.4, 56mm 1.2, UWA 10-24 F4 OIS, 14mm 2.8 etc then why on earth should I invest in DSLR or these new lenses being released by canon, sigma etc while I get a huge advantage on other things while only sacrificing a very little in quality or any other feature?
High ISO. The Fuji system uses crop sensors exclusively, AFAIK, whereas most of Canon's lenses are designed to accommodate full-frame sensors in their higher end cameras. For indoor shooting, that extra bit of surface area makes a huge difference.
As far as most image quality attributes go, images produced with Fuji cameras are essentially indistinguishable from Canon 16mp FF sensors. The only significant difference is the extra degree of background blur that is possible with the FF sensor. But this is where is gets really interesting. The Fuji lenses are very nice. They are also fairly sharp wide open. I'll throw it out there - does anyone really use the Canon 50/1.4 and 85/1.8 wide open when they are seeking sharp images? I suspect not many. But you can use the Fuji lenses wide and get very nice results. The Fuji lenses also produce nicer bokeh. Given that you might be more likely to use the Fuji lenses at wider apertures than comparable Canon lenses, even the background blur argument probably results in a tie.
The key benefit of the Canon system is that there is such a wide variety of cameras, lenses and accessories available. There are also a lot of specialised equipment such as tilt/shift lenses, fish eye zooms, big white lenses etc that many manufacturers don't have. Compared to Fuji, the Canon flash systems is noticeably more advanced. Most camera/lens combinations will focus faster. And if you are into sports and wildlife, shooting with Fuji is an exercise in frustration. For many reasons, Canon is the sensible choice.
Still, I bought into the Fuji system, and while acknowledging its many weaknesses, for everyday photography, I think it is awesome.
I read the comments above about mirrorless wildlife shooters with a smile on my face. I'm sure those people exist. But I suspect most people buying mirrorless cameras are more experienced photographers who are realistic about their expectations. As long as you don't believe any of the hype about "world's fastest AF", but understand that AF speed is fine for things that aren't moving fast, you can't go wrong.