I believe the reason was because the older Li-Ion batteries couldn't supply the current that was needed for startup. The newer ones can. But like I said and mark said, you need the nose weight anyway for the Reaction and Ni-Cd's or Ni-mh's are probably about a 1/4 of the cost of the Li-Ion or Li-Manganese. My Ni-Mh 3300mah car pack was about 25.00. I think the Duralites start at 100.00 and as far as fast charging goes, I think you better check that. I can charge my 3300 pack at 5 amps if I want. I'm not so sure I'd try that with a Li-Ion.

Marty