Not able to install off line (or downloaded) snap files

When I try to install a snap file, Gnome Software shows an alert saying the file is not supported. The only way to install a snap file is opening a terminal and calling snap install with --dangerous flag.

It is true that Gnome Software handle the snap installation in a very intelligent way, using the store and proper channels. But...

- Some developers does not want to be locked to a store in order to distribute their applications.
- Some softwares cant be made available at a store because of specific purpose, or licensing, or very specific or restrictive network environment etc
- It is far from being friendly to ask the user to open a terminal in order to install an application

Snap would be THE solution for computers without Internet but unusable for users that don't know how to use the command line. I understand that this can be something bad for security, but Gnome Software could alert the user he is installing something that is not on the official channel.

Really, being able to install off line snaps is essential for a lot of users.

Thanks for your attention ;)