I'd much rather the Panasonic VL2020 that's fitted to the Blizzard 1260 than any kind of non-rechargeable CR2032 or barrel battery.
Varta doesn't seem a quality brand to me, not going by highstreet AA-size batteries anyway. Then again, Duracell don't make rechargeables like those new 2,700mA quick chargers.
There must be big potential for making battery plug-ins for Amiga. Remember the old parallel port clock adaptor? Then there was the rare clockport clock, the RAM expansions with clock, accelerators with clock, motherboards with surface mounted clock.