I’ve only tried it a few times with my french press but plan on experimenting with it over the summer.
I’d also veer on the side of immersion, those drip machines are quite big and seem to be really only usable for cold brew, though adding more functionality might be an interesting avenue. I think the product could be much more practical if cold brew is a viable option. In that article, they mention that the french press made decent results with the first coffee type they were using but really fell short with the second. I’m wondering if their recipe was really on point for that second roast or if certain roasts are preferable for cold brew and specifically immersion cold brew. Getting your own drip machine and getting a feel for the different methods might be needed. 
If immersion cold brew is possible, the product could even be more of a filter adaptable to many pots. Heck it could be as simple as filling a big tea bag with coffee.