Sodium-ion batteries are starting to be deployed in battery electric vehicles.
Technically true. It has happened exactly once, in February this year, in China.
Sodium-ion is better for stationary storage than Lithium-ion in terms of cheaper cost, 0 to 100% charging range, better for the environment as Sodium is abundant, and a lower risk of fire.
The downfall of sodium-ion batteries since the '70s has been their very poor longevity. Even today, the best they can do is 900 charge cycles before their capacity craters. Lithium-ion tolerates 3500 cycles today, and can be coaxed to last much longer with careful charge management. That same careful charge management is required to achieve 900 cycles with sodium-ion too. If you pursue 0 to 100% it's much worse.
Sodium-ion batteries also use all of the same materials as lithium-ion, despite best efforts to the contrary. That includes manganese, magnesium, and nickel. Efforts have been made involving titanium-bearing cathodes, which are interesting lab curiosities but ridiculously expensive in bulk.
Development of sodium-ion batteries is 20 years behind lithium-ion. They enjoyed research attention through the '80s but that tailed off to essentially nothing in the '90s. Research didn't pick up again until the 2010s, so finding reasonable cathodes, anodes, and electrolytes are all behind where lithium-ion now is. It's going to take just as much experimentation and failure to advance sodium-ion even as far as lithium-ion.
Personally I don't like either sodium-ion or lithium-ion for stationary service in homes, because they just don't last long enough. Home appliances should have 30+ year lifespans and that includes battery piles. I'd prefer nickel-iron batteries if their own shortcomings could be worked out. (They have a nasty tendency to develop a lot of hydrogen gas at the slightest provocation.) Nickel-iron batteries have the proven longevity to be suitable for consideration as a lifetime battery, with original Edison cells still in operation today, running at 50% of their rated capacity 100 years after they were manufactured. Unfortunately mobile applications have dominated battery research for decades so nickel-iron has been ignored. Their energy density is low enough they've been dismissed out of hand, but that's not an issue for stationary applications (within reason, which they meet).
Of course the other problem with nickel-iron is they last too long. Commercial companies like products which last just long enough for the customer to feel satisfied and not a minute longer, so they have to come buy a new one and are willing to do so. This is why we can't have nice things.