Stick with me here. There are plenty of old arcade games designed to be played under this format, now without a modern console hardware solution that can accommodate them. Consider how well this would work with shooters and pinball games. Nintendo could release a special Joy-Con with side grips and re-spaced buttons to make the portrait gaming experience even more comfortable.
Or consider a vertical stand for the tablet with both players using the Joy-Cons individually. The limited button set and awkward positioning wouldn’t be *as big* an issue for these kinds games.
Nintendo (and everyone else) love to capitalize on opportunities to churn out obnoxious new peripherals. Ditto new editions of old, existing games. Vertical gaming promises both, bundled in novelty. Are there any other boxes to check?
Swing for the fences Nintendo.