Afraid to carry spare batteries . . .
hardly.
Here are some casual observations after years of ownership . . .
- Low battery can cause unpredictable behavior until they die completely.
- Shelf life of spares are unpredictable.
- Different batteries are not always available in a lot of places.
- Not everyone has one camera or uses one type of batteries.
- Batteries get discontinued.
- Need a coin to open the battery compartment in most cameras.
- Batteries left in can cause corrosion.
- Cold weather affects battery.
- One less thing to worry about.
As already listed, some have designed minimal or no battery dependence which is a very good design accomplishment that not everyone has done.
It is great to be able to say your camera can do without it but even better if you can properly expose film using the sunny 16 rule . . . ;-)