I don't like .kepubs, and I don't like Kobo's setup where it's hard to know if you can download a book in epub or kepub before you buy it. I know it can be done, but it's just another hassle to deal with there. If anything is wrong, their customer support is lacking. And generally I buy books on sale, very rarely at full price these days since I have so many still to be read. And that means Amazon's sale price is usually cheaper.
The point is if you remove DRM, you're not limited to one store or tied to their system. You're free to buy from wherever you like, whether to get the best price or best selection or if you just like the colors of their website better.
I could ask why you don't buy from Amazon (but I won't and I'm not).