The opposite of lead acid, keeping a lithium battery on a tender is bad for it. Charge it, disconnect it to stop the parasitic drains of clocks and devices with memory, and it'll last all winter.
On a related and fwiw note, cell phones can be made to last a LOT longer than most peoples' do. Use a lower amp charger or wireless one to slow the charge rate and don't just let it charge all night every night. Stop the charge at around 90% and don't be afraid to let the charge get low. Never put your phone on the dash in the heat of the sun too.
The AGMs are lasting 5+ years and if buying a re-labeled 14 then they are about $60-$70. That's longer than most people keep a motorcycle and even if you own it 10 years that's still less than a lithium.
Two of my bikes are 20 and 30 years old. My newest bike is the 2012 S10, and I can imagine keeping it until I retire from riding. While the agm batteries are fine batteries, and are cheaper, there are other significant advantages to lion other than cost. Many of us would spend hundreds to lose 10 lbs of weight, for example. ( I meant 10 lbs off the bike, but yeah, it goes for the belly fat too.)
I have been using agm batteries for over 20 years, so I was an early adopter. I heard many of the same arguments about cost/value comparing them to "wet" batteries back then. But owning many bikes, it was worth it to have the slower discharge rate, higher cca, and no maintenance. Not to mention longer duty cycles. I typically got 7 years out of expensive Odyssey batteries, while lead acid in the same bike were doing well to last 3-4.
So it's worth the expense to me. Everyone has different needs and wants.