I've been looking into the same thing and as far as I can tell it really only applys to mechanical heads because crossbows typically shoot faster and they don't want them to expand in flight.
Mechanicals..... SOME mechanicals have a tougher/tighter blade retention system to keep the blades from deploying in flight. Others....its just marketing and a way to charge more.
I switched from mechanicals to fixed blade old school muzzy 3 blade heads and am thrilled with the performance. They actually shoot closer to the FP than the mechanicals in my set up and punch a scary hole that bleeds really well.
Im agreeing with everything stated above, Marketing.
If there was anything that actually DID matter it would be mechanical broad head deploying mid flight. The "crossbow" mech. heads have better blade retention. The guy at the archery shop told me if your crossbow is shooting 340 and bellow you wont have any issues with mech. heads.
Although the difference is mostly "marketing", SOME crossbow-marketed broadheads are made "heavier" than their comparable heads "marketed" for vertical bows. A good example is the Slick Trick "Crossbow" head which is 150 grains, while the comparable Slick Trick normally used is either 100 or 125 grains. Heavier heads will usually fly straighter (at a loss of velocity), but that's true whether vertical or crossbow. So it's still "marketing".
As others stated I think it only applies to mechanicals. I used Rage 2.3 crossbow broadheads on a recommendation this year and got full pass through straight through the lungs. He didn't run 30 yards or so. I also don't think you can. Up the Rage 2.3 for regular compounds. Supposedly the securing collar is developed for very high FPS bows. So that being said if your compound is rigged for speed I'd bet they still work. The broadhead doesn't know what it's being shot from lol. I did a lot of research on mechanicals and crossbows and read many articles of people using regular mechanicals and either getting deployment prior to impact or having deployment issues on impact because the heads weren't developed for those speeds. Just my opinion I wouldn't risk injuring a deer that I couldn't recover therefore I opted for crossbow mechanical heads. Obviously not a concern for fixed. Just be sure whatever you choose always check your zero. Rage 2 advertised to fire like FPS but with the practice head I was shooting about 3-4in low at 30.