Do they NEED protection? No. Though For any mech its probably advisable to use a protected battery. There are penny fuses (not a penny, but cheap) that can be used to protect an unprotected battery. But common sense is enough to say that when you feel the atty is no longer giving its best, its time to change batteries. I have been using mechs with unprotected batteries for ages with no issues whatsoever. I don't use a kick and never have yet so can't say anything either way on pros and cons. edit- I would say that if you don't already have batteries, then buy protected batteries for the mech you are getting. But if you already have unprotected then just use them. The mech of choice can mean some batteries fit better than others.as an example, Flat top unprotected fit the hammer mech better than button tops or either of my two protected batteries (similar in height to an unprotected button top despite being flats).