You don't have to use the charger and rechargable batteries... it works very well on four standard AA batteries. Use standard rechargable AAs if you wish. Everything's in flash, you can leave batteries out of the unit as long as you'd like with no fear of losing anything. The charging cradle and NiMH battery pack are nice to have, but not necessary. That's why they're an option...

My pre-production unit is still running just fine on the original batteries. It only draws 65 micro-amps when it's asleep...