button cell and a small
of similar size. Not
advantage.
with power budget.
spring holder.
Using a metric of energy per mass, lithium batteries are better than alkaline.
Regarding low voltage equaling low power, this is not always true in analog design. I had a market type go off in a rant when I specified that a 3V version of an older 5V part would draw higher current. Hey, if the power load is the same, less V means more I. You will be doing well to keep the power the same. This idiot eventually got promoted to direct level. That's Maxim for you.
[Sorry, I don't have any insults to offer, just technical information. ;-)]