Why would discovering life on another planet be important/matter to us? I had a funny thought, and would like to pose it to you:

When I was a kid, reading any kind of astronomy or similar books would all say that there was no other life in the universe, and made it pretty clear that anyone thinking there could be was probably off his rocker. 

Nowadays, it seems this has become a very important question for astronomers and other scientists, a new deep-seated belief that must now be proven. Some seem to think it would be the most important discovery of all time. 

I'm wondering why?

My guess is, if we did 'discover' life on another planet, it'll make the news for a bit, and then the average person will go back to their every day life without much more thought about it. 

For me, I would think this is great, only insofar as it means a possible new source of food (i.e., some delicious exotic cuisine assuming it's edible, and possibly even some place to go conquer and colonize if there was any profitability/money in doing so). 

For some scientists, though, I get the sense it's more of an axe to grind with the long-dreary he-said she-said argument of science vs. religion. 

Why do you think it would matter?

My question assumes any life discovered is probably not going to be very 'interesting' life, at least nothing we're going to have a conversation with.
It will be very important in several different ways. Not as in Messiah having descended to the World, and maybe not during one single human lifetime. But it will profoundly change the world in our minds, and thereby change our collective long term actions. The next generation would grow up taking alien life in space for granted, their minds will be more different than we old guys can change our stiff brain flesh. Like Newton's physics dominate our everyday life now, even for those of us who don't understand how all of physics has been deduced.


If life survives in other places than Earth, then maybe we (as in life from Earth) can do so too in the future.
If there's life in other places than Earth, then maybe we came from it? All life on Earth is family, all living things are closely related with each other. The question of our origin has always had high priority in human minds, see all religions.
If alien life is biologically similar to that on Earth (as in using DNA and proteins) then we could use it as a huge laboratory for medicine and environment control and agriculture and what not in life science. Astronomy today contributes to physics in our everyday life by studying a laboratory (the universe) with scale far beyond what humans could ever construct. If biology could do the same, we would soon notice the results in the shape of useful products.
If alien life does not use DNA and proteins but is very different from us, then I can't even guess what discoveries would come out of that. Zweistein.
If alien life is not found, even when we have searched long and hard, then we can gradually make the greatest discovery of all times: That we are unique and special. Searching for ET without finding it would be the most mind boggling thing imaginable. I don't think this hypothesis has been well addressed yet, I suppose no philosopher knows even where to start.