where Li batteries outshine (pun intended) lead acid is the ability to deep cycle more often. So if you are using your 12 volt battery to run things without charging at the same time (like my travel trailer when not plugged in), you run the battery down and it has to be recharged, Li batteries can do that many more times than lead/acid. Also Li batteries can hold a charge longer without use than lead acid. Having said that neither Li or lead tolerate deep deep discharges, so many Li batteries have that internal control to turn them off before that happens. Neither tolerate over charging as well.
In your normal car/vehicle the battery is being constantly kept at charge by the engine running. and so should last a long time. However, most motorcycles have really small batteries with small plates and hence they generally do not last long. When you want good cold cranking amps in a light weight small package you loose longevity.
