PS What does the term "12 Amp Hours (PbEq)/ 6.1Ah (Actual)/ 78Wh" that I copied from their website actually mean?
The recommended Ah capacity of LiFePO4 motorcycle batteries is typically around half that of the standard lead acid battery. You can believe that it is actually 6.1Ah. The questionable part is claiming "equivalence" to a 12Ah lead acid battery. What parameters, exactly, are we talking about?
I'm pretty sure the answer will be in the cold starting amps; a 6.1Ah LiFePO4 will meet whatever cold start test a 12Ah lead acid battery will meet.
I want to point out that no motorcycle actually needs 12 amp-hours. There is nothing on a motorcycle that needs to draw 1 amp for 12 hours, or 100mA for 120 hours. Rather, in order to meet the cold starting current tests, a lead-acid battery sized for 12Ah is typically required. The amp-hour capacity is just a side effect of sizing a lead acid battery to meet the current delivery tests.
Starting a motorcycle uses a small fraction of one amp-hour (work it out: 150 amps (say) for 5 seconds (say)). So it doesn't matter at all that the lithium battery is only 6.1Ah. There's enough capacity for dozens of cold starts.
There is one advantage to a larger capacity battery (ie in sticking to lead acid). Most modern motorcycles have a small residual current drain on the battery, typically for the clock and any anti-theft electronics. That is often enough to flatten the battery over a winter lay-up. Your 6.1Ah battery will go flat in half the time. That might be important, but in reality any motorcycle layed up for winter ought to be connected to a charger regardless of whether the battery is lead-acid or lithium.