This again is why modern gamers are just fucking impossible to please. Bethesda gives you BOTH options. If you need to get to a planet from one solar system to another, you CAN just press a button and be on that other planet, or in its orbit if you haven't been on it yet.
But that's just it, you CAN instead pull up your starmap once that mission is active, see the star you're at, and all the little dots youll follow to get where you're going. You can then jump to each dot on the way, look around, scan planets, get hailed by ships, visit places your scans found, etc on your way to your mission. Doing this, you'll often get sidetracked with another mission, the choice is yours. They dumbed down interstellar travel as hard as they could without it no longer resembling what interstellar travel would be like.
I'm of the opinion thats what Bethesda wants you to do, and the fast travel is just for people who want to level/"beat" the game quickly as its own end instead of taking it all in, possibly and understandably due to player time constraints.
Fast travel is a convenience feature. People would be bitching if it wasn't in there. Sometimes you just want to zip back to ~~Whiterun~~ ~~Diamond City~~ New Atlantis to sell some crap.