Sodium-ion batteries have started to appear in cars and home storage

If sodium batteries are so much cheaper, why is the emphasis of this article on batteries for trucks and not grid-scale storage? Isn't the latter much more impactful?

Also naively I would expect sodium batteries to be heavier that lithium, which would make them worse for transportation but still fine for energy storage.

Probably familiarity bias; the author has more contact with EVs and/or expect the reader to have more contact with them.

I haven't seen any inverters for grid purposes for the wide Voltage range that Sodium produces. It may be the inverter organisations haven't got their yet and are waiting for the batteries to be available and cheap before it makes sense.

I think a lot of households will choose Sodium just because of how cheap it will be but not until there is the basic inverter equipment to make use of it from the usual manufacturers.

They haven't produced many yet. And when they do they'll probably sell them for applications where they can charge most and make profits. The Pioneer Na(sodium) portable power station thing in the article isn't cheap. The grid storage will come when production ramps up.