That's true, lithium chemistry batteries work best in a temperate climate, if they get cold it slows down the chemical reaction and lowers their peak discharge, like a dead car battery after a sub zero night. AGM batteries might work okay in hot temperatures like in AZ, but they still suffer from slow cold discharge. They also weigh too much for bicycles, my lil razor dirt bike is 120 lbs with 5 12v 10ah SLA AGM batteries, but at least I can afford the pack at $100, and it won't catch fire. I still don't trust any of those shrink wrapped packs made for bikes out of knockoff 18650 cells soldered together, if it craps out you lose your "fuel" investment, and if you abuse it or there is a manufacturing defect the battery can malfunction or cause a fire hazard. I think if I go about making an electric bike using Lithium batteries, I will probably use a series chain of 12v automotive deep cycle LiFePO4 direct replacement batteries, so if one get messed up or has balance issues, it won't munch a whole $600 battery pack. I just can't justify the risk inherent in purchasing an expensive battery pack at this point, the news about hover boards catching fire leads me to believe that the batteries are of unknown varying levels of quality, the knockoff Samsung cells being a major issue with the common shrink wrapped or vinyl wrapped packs.
In short, electric motors used within operating voltage specs are bulletproof, controllers are as good as you pay for. Electric bike and scooter batteries are the new Happy Time - Unknown levels or quality control, with spec sheets which should be taken with a grain of salt. User experiences and results vary widely depending on manufacturer and individual unit. Unfortunately if you get a bad one, the only hope is to try to claim a warranty if still valid, or tear the pack open and start replacing dead cells, which are spot welded to the bus bars usually.