This is why I am on Kindle as well. I enjoy the "Whispersync" Audible/Kindle integration and multi-device support.
For those that don't know, Whispersync is easily the Kindle's "killer feature". It syncs your location in the book across all devices (I use iPad, Kindle Paperwhite, and iPhone, Sonos, Alexa, etc). So if you read a chapter on your phone, and then go to your Kindle later that night, it will keep you in the right location. But even more impressive is that you can skip in and out of the audible versions at will as well, and stay in sync. So I can literally read a book on my Kindle one night. The next morning I can read a chapter on my iPad. Then I can jump into the car at work and listen via the Audible CarPlay app in my car. Then I can read more on my iPhone via the Kindle iOS app while I wait for a meeting to start, then I can listen to the Audio version on my Alexa in my office, come home and listen to the Audio version on my Sonos speakers while I cook dinner, and then go back to my Kindle as I settle down in bed for the night. Seamlessly staying in sync across all these devices. It is really awesome, and makes the Kindle worth it in my opinion.
The new Kindle Paperwhites also support Audible on them via bluetooth headphones and you can listen while you read along.
I literally just purchased a book about 10 minutes ago and added the audible narration. I don't maintain an audible subscription because I have found that I can often buy books + audible versions bundled together for the same price (and often less) than a month of Audible. So I prefer to just buy them ala-cart with the kindle book bundles. It is a better deal.
I realize that I sound like a fanboy, and I am. I'm a huge fan of the kindle. It isn't perfect, but until another ecosystem can match the audible/kindle whispersync feature with apps on literally every device (including smart speakers, ai devices, etc) then I will stick with Kindle, even if the books are more expensive, because it is just easier.