Yes the portmanteau names are a bit ridiculous. Selling them through a site like that not ideal and it's not clear that you are paying for well cared for pups.
However if we take that particular seller out of it and assume that the dogs are well cared for and of suitable temperament, wrt to the idea of whether cross breed dogs of a particular mix are worth money, why not? They are still dogs. They will wag their tails and go on walks etc? If someone likes dogs with those particular features, why shouldn't a cross breed dog be worth money to someone?
Pedigree Breeds started from somewhere. They aren't superior to cross breeds. In fact we now know that there are huge health problems within pedigree breeds, especially those with low genetic diversity, which have become ever more exaggerated in their features. We know that the Kennel Club is only beginning to catch up to the idea that it has a responsibility to look after breed health, and still Note that failure to carry out DNA tests or Health screening does not prevent a breeder from registering puppies with the Kennel Club.
Dog Breed Health
Don't assume that because a puppy has a pedigree that it is healthy or cared for.
They've even created an Assured Breeder scheme (which basically seems to be an extra payment for promotion on their website...) , to confer some sort of quality standard that people might assume that regular pedigree guarantees, and even that falls completely flat.
It’s important to note that even when health testing is ‘required’ a bad result does not prevent a dog from being bred. So even if a dog has a poor hip score or is found to be affected by a disease from DNA testing, it can still be bred.
Dog Breed Health - Assured Breeder Scheme
So pedigrees don't mean what people seem to assume they mean anyway. You really, really need to do a lot of research to know whether your pedigree is worth the extra money you pay for it. A cross breed from a knowledgeable, loving home where the bitch and pups are kept in good health and socialised is just as safe a bet as a pedigree dog from a similar background. It is good [informed] people who make good homes . Not a piece of paper.
Of course there are many rescue dogs waiting for good homes so if you can consider that option it is better to.