Japanese oven market is very different from US market. Most people use countertop ovens, that plug into their cursed 100V mains and draw 15 amps max. This is less power than most handheld blow dryers. For this reason, size and efficiency is crucial.
Their ovens are mostly microwave/convection. That is, you can microwave in it, or use it as a conventional convection oven.
Panasonic and Hitachi have offered a grill feature for years that uses the microwave to heat up the oven tray for grilling. With that, you can cook conventionally (convection or radiant,) and at the same time use the microwave, but to heat the pan, and not the food. The adds show tons of uses for this feature, but in reality, I think it is only useful in convincing people to buy their ovens over a competitor.
The market is very competitive, and the 4 main manufacturers are always coming up with new things to stand out. Hitachi weighs the food to help automate with cooking time. Panasonic had this grill feature. Sharp uses superheated convection with all the heat coming from the air. Not sure what Toshiba is doing lately, but they had an arc shape for refraction something a couple years ago. They all offer steam for baking, etc. etc.
The appliance market in Japan is very trendy. I have a "fuzzy logic" washing machine, an "ion generating" fridge, and induction rice cooker, and inverter A/C, etc. My estimate is about 3/4 of these marketing trends are nonsense, but some are useful in improving the product.
Oh yeah, New releases generally cost well over a thousand $US, and the prices drop just south or $500 after a few years for a standard household oven. Japanese houses are small, they do a lot of cooking, and they can not put in an AGA or a granite island, so they spend a lot of money on their microwave.