Really? Just show which one is that .deb app.
First, I am NOT complaining, and I never do.
Second, you don’t have a single (working) .deb app in your Ubuntu system.
You have files and folders, but nothing called a .deb app. The same way, you don’t have a snap app, only some files and folders inside a snap folder, which needs another app run them. These files/folders are not squashed (sorry, @popey not like in AppImage. Just reinstalled “snap” gnome-calculator to check) and they contain the same files and some other files in that folder.
Normally, when you click on the icon for the given app, it simply runs the relevant exe file in the /usr/bin. So, the app starts immediately. With the snap, the /usr/share, /usr/bin, etc are in the app folder in the snap folder and it takes some time for click to get registered, so the lateness. Maybe, the guys behind snap would find a way around this, and maybe one day the “snap” apps would boot just as the normal ones. There is some sort of a runtime app that’s slowing it up. At the moment this happens in the first time you boot your “snap” app, and every time after you reboot your computer.
A “snap” app would boot equal (in terms of time) to the normal app in your Ubuntu system, but never faster. If you are interested, have look at the folders inside /snap directory. Normally, a click would send a message to the file in /usr/bin, and now with a “snap,” it’d have to go to /snap > then to the named folder > and then to /usr/bin inside it. Maybe, even go through some other places.