Internet says that Kobo, like Kindle, sells a license to use the ebook, not an actual ebook file in a transferable format such as ePub. Internet also says you can strip the DRM (the acronym stands for Digital Rights Management, an anti-piracy measure) from a Kobo or Kindle ebook. But I believe that still does not produce an ePub or PDF file that you could, e.g., save to your computer to read, email to a new computer, or otherwise pass around.
What it does produce is a Kobo or Kindle file that you can share with someone else's Kobo or Kindle e-reader, which is one definition of piracy. (Use the "lend" feature if you want to do this fairly.)
I went through the "how to save Kindle books to my computer" thing a while back and while I could save the files, I couldn't *read* them except in the Kindle app, so there was no point.
It's all about piracy. Most authors make little enough money as it is. If people can send whole electronic books wherever they want, they tend to share them with other people who have not paid anything to the author or publisher, which is another definition of piracy. Someone who receives an ePub or PDF can also straight-up steal it, change a few names, and republish it - or feed it to an AI.
If it's important to own an ebook file that is completely transferable and platform-independent, the best thing to do is buy it direct from the author or publisher, if they offer that option, or from Smashwords if offered there. An ePub file bought from author, publisher, or Smashwords can be sent to a Kindle or Kobo e-reader.
Note, an author/publisher is breaking contract if they list a book on Smashwords while it's in Kindle Unlimited (KU). KU exists to make books exclusive to AMZ.
Sub-note: all of my titles are, or should be, listed on Smashwords! There’s been a system conversion that resulted in some broken listings, so tell me if you’re looking for one of my books there and can’t find it.
It's an imperfect system, but so was the old-days system of trading in used books for resale. Authors never got paid a cent for that, even when books became "collectibles" traded for hundreds of dollars.
Authors *do* get paid when a library licenses an ebook or purchases a hard copy. They don't get paid every time the book is checked out or read. But if demand is high, the library is likely to license/purchase more titles by that author. So if you want to support an author, avoid the license situation, and can't find a legit transferable copy to buy, get books from the library when you can. And review them!
My personal take on the situation is: on average, I read a book a day, and I can afford to license or buy them. It's better for authors if I license a book at a sale price than if I simply don't buy it at all, because at least a sale-price license shows up as a sale on their records, which pushes them up the "also bought" algorithm and helps other readers find them. Especially if they are AMZ-only, as many are, because publishing is difficult and many people can only cope with doing it on one platform, and even though J. Bezoar is a dick, the Kindle platform is relatively easy and cheap to use and provides the best possible exposure for an author.
tl;dr - I don't punish AMZ-only authors by not buying from AMZ, and I don't punish *myself* by complicating my life using different e-reading platforms and devices. Kobo is part of a huge public company guilty of all the same capitalist pig behaviors as AMZ, because their first interest is serving their shareholders and their political connections, not serving authors or readers. It is what it is.