Everyone understands the paradigm of double clicking an icon to launch the program or an installer. Many aren't going to understand the exact command they need

Everyone understands the paradigm of double clicking an icon to launch the program or an installer. Many aren't going to understand the exact command they need to type into a terminal to get it to do what they want. This is almost always the answer for why people don't want to resort to using a terminal, discoverability. You can look it up, of course, but there's no good reason imo to not include GDebi for users unfamiliar with that workflow. Other distributions have it by default, but Cannonical is favoring their own tech here over the needs of the users. One more useless roadblock.