If your skis have a waist width of 108mm or more, 130mm brakes are really the way to go. The brake arms need to clear the edge of your ski when they deploy—if they're too narrow, they'll sit on top of the ski instead of dropping down, which means they can't do their job of stopping a runaway ski after a release. That's a safety issue you don't want to mess with.
On the flip side, don't put 130mm brakes on narrower skis just because you might use them on a fat ski later. Those wide brake arms will stick out past the ski edges and drag in the snow during turns, which is annoying at best and can actually affect your skiing at worst. They can also catch on crud and get damaged.
The sweet spot is matching your ski's waist width plus about 5–15mm of clearance. So if you're riding a 115mm-waisted powder board, the 130mm brake gives you just enough room to work properly without excess overhang.