First of all, the cassettes are returnable. This is also mentioned on their website. * https://daan.tech/discover-bob-cassette/
> Each Bob cassette is returnable and reusable. We refill them and put them back on the market. Close the loop, lower your carbon footprint.
You're also NOT required to use the cassettes. You can just throw standard dishwasher tablets in. This is mentioned in Bob's manual, and probably on the website as well. I've been doing this for years and had no issue. There is no DRM-like aspect to Bob.
And finally, it's not a worse washing machine as you say, it's just smaller and more flexible (wrt plumbing), and as Techmoan mentions in his intro, this is a very strong advantage of Bob for people living in small European apartments.
(source: owner of Bob)