Every bit makes a difference. If you don't have any type of fuge allready on on your 75 gallon, I would do it.
I wouldn't waste my time with it if it made my tank look any bit less appealing. Thats just me though, I don't like hang on the back stuff...I have a bunch of HOB
stuff in my 37 gal
and I hate it. I just don't have any room for it in the sump under the tank.
Back on subject though, Doing the fuge will give you more water, better filtration, more water flow, ect ect....Basically more stable conditions and cleaner water. I'd go for it.
I'm a noob though lol...so ya might want a second opinion.