@Bernardo: The original booltool was done by vitorbalbio and I think they have mostly just been working on the Motion tool since it was put on the blender market. This seems to be a Russian company making modifications to it. As far as I can tell. This is looking very promising. Hope they make an official announcement to it. This would be very helpful in making some base meshes for hard surfacing.
This is Genius
Thanks for the explanation! 
I am a little confused here - isnt this just a combintion of boolean remesh and subsurf?
YES, very very cool
a discovery and either
i too tried the settings in the OP - but like you don’t get clean results like in the OP videos. My tests look like the second and third images above.
Almost right
Booleans first, then remesh, Bevel, subsurf
boolean and remesh.blend (484 KB)
Attached an example Blendfile.
Pretty cool - too bad this does not work well for hard edge (product) modeling. But it seems to be a pretty fast approach to do some organic shape mock-ups.
Actually can instead use had to surface, the bevel is to it and you can still use the crease.
But here’s the thing, remesh isn’t exactly, reliable.
This would have made an awesome gsoc project! 
We need a new booltool that is as awesome as the ones presented in this thread.
I am flabbergasted. This might make me want to use booleans.
This is about an essential need in 3D modelling: having smoothly shaped bevels and fillets in boolean seams. It is the thing that the attention of the authors of Groboto and Mesh fusion has been focused some years now, with very satisfying results. Having such a thing in Blender would lift up the whole app to a quite new level, regarding its modelling means.