If you simply use what the program gives straight away without tweaking and working with it, then they are, for the most part, correct. I think a person mentioned creating solos and this is a really great application. You can generate multiple versions of a solo, each being a little different (I think the app will go through at least 4 variations) and then you can comp from there if you like.
That's a very good point, but I think that for the most part,the people who use it because they don't wish to do a lot of tweaking an/or using a daw with it, like why people use arranger keyboards. Many daws usually include some sort of basic melodyne
type of program where you can take a mono soloed sampled instrument from the plethora of samples available and create multiple variations. It's really about what expectations a person might want from the program whether it's worth it to them personally or not. So for someone who wants to buy one self contained program as an arrangement solution, it very well may be the best choice, however someone who wished to get intimately involved with sampling, there are plenty of better options