|You'd best have a dialed bike for this!|
It's a "double-whammy" of marketing hoo-hah. You get the 27.5"er wheels on one introduction and the term "gravel grinder" on the other. The fact that it comes from Schwinn, who is said to be looking to increase its independent bike shop dealer presence, makes this stand out even more. Clearly, both bikes are purely exercises to cash in on what Schwinn marketing sees as trends.
The hard tail can be seen as "just another hard tail". Really- 27.5"er wheels are not going to really make a hill of beans difference here. However; the other bike is flat out hilarious. The YouTube clip will show you that not only do the marketers feel that "gravel grinder" is marketable, but "adventure bike", and "versatile" carry as much weight or more. Don't forget that the name of the model has "CX" in it!
It must be said: Yes- you could use this bike on gravel roads. As I have said, you can ride any bike on gravel roads. You can also ride a road bike on single track, but that doesn't make that bike a "mountain bike", or a "touring bike", or anything but a road bike that's being used on dirt. Is there a better bike for that? This is the question a potential buyer has to answer for themselves.
However; this "gravel grinder" term that is being affixed to any bicycle that has larger than 25mm tire clearance and/or disc brakes, drop bars, and 700c wheels is nothing less than "make believe" and consumers had best be careful of the snake oil being purveyed as a cure for your dirt road disease.