I think it's cool that producers are experimenting with co-fermented coffee in search for new experiences, but truth be told, the co-ferments I've had have always left me disappointed. I'm guessing the process is delicate and it's easy to end up with over-fermented, overripe fruity notes that overshadow the subtler coffee notes. I've tried these coffees from several award-winning roasters and the experience has always been similar. The first sip catches you off-guard like "wow, I didn't know coffee could taste like that", but once your palate catches up, it can be a chore to finish the cup. The flavor is intense, but I think it comes at the expense of clarity and depth. It works great for competition where you need to stand out, but not so much for home consumption.
I feel the same way about beer with fruit adjuncts. Yeast and hops -- like coffee -- can express an unbelievable variety of aromas and flavors on their own. For example, a Flanders red ale can taste so much like sour cherries that you couldn't believe none were added to the ferment, mostly thanks to the magic of yeast.
When you have this kind of expressiveness in your ingredients to begin with, co-fermenting with fruit is a bit of a shame in my opinion.
I see what you're saying, but IMO beer is both a bad example AND similar to coffee in many ways.
It's a bad example in the sense that the flavors you get out of fruited beers tends not to be as 'funky' as in coffees because fermentation is controlled so closely. You can get some incredible flavors out of adding adjuncts to beers. Yes it's interesting and cool that you can get some of those flavors out of yeast, but there are also flavors you just can't get from yeast that can be delicious.
It's also similar to coffee in that adding extra things is not somehow new or novel, it's actually very old, we're just rediscovering it.