- WW2 proximity fuzes that had batteries where the electrolyte was in a vial that got smashed by the G-forces of being shot out of a cannon providing power to the radio inside for the 10 seconds it needs to get to the incoming aircraft
- Hearing aid Zinc-Air batteries, that are extremely energy dense because you only have to actually manufacture the anode, the cathode is the entire atmosphere of the Earth
- Missile batteries, which are often Lithium-silicon/Iron Disulfide batteries that borrow some thermal energy from the rocket motor to get a molten salt electrolyte
Where fiber optic is used though, that is the limit. That is a minority though.
There's also payload and loiter time to consider.
If you have a drone that can watch the battlefield for hours instead of minutes that is incredibly useful. Same story if you have a drone that can 3x its payload.