How would you ever know this? How do you know what further discoveries may be made regarding these planetary systems orbiting other stars? You couldn't possibly know.
It's only been a few years now that these discoveries have been made. The advancments in astronomical optics alone and other technologies developed to locate these planets is absolutley remarkable. Conducting studies on stars and planets inside or outside our own galaxy can tell us a lot about our own sun and our own planet.
There is nothing more important than these studies, as Earth has very limited resources and room here. In a few hundred or thousand years, (which isn't that far off considering the age of the Universe) the people of this planet will run out of a lot of resources. These resources are not limitless but the increases in our populations seem to be.
Your lifetime is short and tiny, others will come along when you are long gone. Just as our own sun has a limited life. This information is part of the puzzle they will need to survive in the distant future.
And I am confident, in a thousands years, they they will be laughing at your statement of, "there is nothing to be gained by peering at stars and planets that are millions of light years away. Nothing".
It might be our job, what we were created to do, the purpose of life. Don't be so quick to scoff.
Genesis 1:14
And God said, Let there be lights in the firmament of the heaven to divide the day from the night; and let them be for signs, and for seasons, and for days, and for years:
The presence of signs implies somebody to read signs. Who would that be? Satan? No, of course it's us. We are supposed to be peering at stars; it's our job, man.
My question to you is so what? Must EVERYTHING have IMMEDIATE value to be important? You sound like one of those people that say "History sucks, what does it matter? It does not GIVE me anything!" ALL knowledge has value.
I would also like to add that without some sort of space travel, the Human race is most assuredly doomed. If it was up to me, I would have already been mining the moon and sending teams to Mars... to make a PROFIT!!!
On a final note, the thought that science is a waste of money is what drove Bill Clinton to cancel my beloved Super-Collider. You see, the benefit wasn't IMMEDIATELY obvious to the powers that be. That is a very short-term and rigid outlook. We could have been doing great things right now, IMHO.