Sodium is not competitive with lithium for energy density, as measured in joules/gram.

Sodium is good for stationary deployments. It's not good when weight matters.

I wonder how well it suits home storage? Not being violently flammable would be a bonus for homeowners

I'm not sure how it's held in the proposed batteries, but isn't pure Sodium violently explosive when in contact with water?

Batteries aren't pure sodium. Pure sodium bonded with something (eg: chlorine) is less explosive.

Sodium + water is, unfortunately, violently flammable.

Add water to elemental sodium, and you get heat, hydrogen gas and sodium hydroxide.

Any concentration of energy (gasoline, batteries, compressed air, etc) is always a potential bomb if it is released too quickly.

The safety problem with Li-ion batteries is the electrolyte is a flammable organic solvent. It is unrelated to the amount of energy stored in the battery under normal operation.

Sodium battery production mosdef benefits from lithium's advances.

As you know, each new chemistry (and anode, cathode, etc) opens up new niches, use cases, and price points. Sodium won't displace so much as compliment lithium.