I think that this is a very nice and simple idea for a game that has to be made in three hours. I am also not a big fan of clicker game, but I completely agree that it is fascinating that just clicking can be entertaining. It is really just the numbers going up that can already make a game fun for some reason. Weird humans brains XD
What you see in a lot of clicker games is that there is a lot of 'game juice'. Like particles flying everywhere, screen shakes, sound effects, etc. I think this is actually a really important part in making clickers games fun, which I missed in this game a little bit. Of course I completely understand that you did not have time for this in three hours, but perhaps something to think about if you decide to continue with it :) By the way, do you know the program 'sfxr'? It is a really easy to use program that allows you to make sound effects in a matter of seconds. Really useful for game jams :)
Otherwise really well done! Especially if you are not so familiar with Unity and you made this in three hours. That is really impressive :D I remember my struggling around with Unity and it is very unintuitive a lot of the time. Also the art was really great! I am a big fan of pixel art ^_^