Praised by whom? The btwin folder is a low-rent and low quality version of a Dahon-style Chinese fold-in-half folder. That folding design is about 95% of the folding market, and has no clever design features whatsoever. It is simple to manufacture, has no patents, and is pretty bad in general riding use. It is neither fast to fold nor compact, and is very bad in customization, particularly with regard to the rider's reach. And it is really, really boring. Dahon and Tern have some okay bikes of this design, but the entire rest of the design category is dominated by bikes of quite poor quality, including the btwin.
Praised by most customers, probably. As an engineer I appreciate Bike Friday's attention to detail and I own a good few "artisan" devices myself, but the reality is that most people want a mass-produced bike that is "good enough" within their budget.
There's no doubt that your bike is higher quality than the Decathlon one, but the average customer doesn't appreciate how well engineered it is or how many patents (??) are involved.
The Decahlon folder folds faster than a Brompton. A friends of mine has both and he's trying to convince me on buying the cheap decathlon bike over a Brompton. The demonstration was convincing.
I'm a big fan of the fact that you can push a Brompton while folded. A feature that other folders miss.