5G does not mean shorter waves/higher frequencies, that's just a common deployment. In Sweden we have 5G on the 700 MHz band, 5900 MHz, and several others in between.

Not everyone has cable/fibre/wifi in their homes, and need to resort to 4/5g cellular services in order to be online.

This product is aimed at those people who want something nicer than the 5g router bundled with their plan.

Back in school, I had a teacher who was in charge of installing 3G, 4G, and 5G antennas for a carrier in France. The answer is that the 4G frequency bands are saturated, and they pushed 5G mainly to relieve congestion on the 4G network. Theoretically, 5G has just as much range (maybe even a little bit more with beamforming) on the 700 MHz and 800 MHz bands.

5G has lower latency again than 4G. There's also more capacity making it possible to use it as a real connection than just backup.

I’ve worked at companies with cellular failover for the most critical services.

5G in my city is 650 Mbps and is honestly cheaper than fiber, but my fiber has better jitter (and can go up to 2 Gbps). For a lot of people, 5G would be more cost effective.

See living near a concert venue. 4G behaves badly in a terrain of 100k phones

Where I live, all the 4G is oversaturated and really slow.

It'd be a good option for failover Internet.