I am areal fan of rechargeable batteries. i do carry lithium primaries as last ditch backups, for the same reasons - they are lighter and very durable. What I will do with my 18650 lithium ions on long trips, is carry an extra lithium-ion and when the one in the appliance gets low, swap it out and get it recharging while the appliance continues in service.

i can theoretically go forever, working like that....

Forme,the higher energy density of lithium-ion batteries is worth the slight additional weight. For short, intermittent use, this is not a factor.