On pretty much any tire, the difference between having a wire bead vs. kevlar bead only amounts to around a 50-100g (less than a 1/4 lb) weight difference.
If there's a pound weight difference between those tires, it's because the wire bead version has a thicker casing 2-ply casing, and is intended for downhill, while the kevlar version has a 1-ply casing and is for XC/Trail/light freeride use. Check out the Kenda website, it says that specifically.
Pretty much all Downhill tires come in steel bead only, the only exception I know of is the newer Maxxis UST DH minion and highroller which are kevlar bead. Many freeride tires are available in kevlar and/or wire. Having DH tires is the way to go if the majority of your riding is lift served, but they are a ***** to ride up hill. They are much more resistant to flatting and can be run at lower pressures for better grip. If to do more trail riding, get 1-ply kevlar tires. A good compromise is to take a ~1200g DH tire with a harder compound (like 60a) and run it tubeless - it will stand up to a beating, but be lighter because you're not using a tube, and the rubber compound will roll better than a soft tire (like 42a).
I just picked up some Maxxis High-Roller 2.35" L-UST tires, they're as light as any other compareable 1-ply kevlar freeride tire, but are tubeless and have a fairly stiff sidewall. They air up super easy, roll well, and grip well.
