Well, I think it all depends on why someone is buying a Chromebook.

Is it because they want a cheap clamshell with a keyboard? (Tablets adjust poorly to this use case.)

Is it because they want a cheap general-purpose computer?

I've seen enough non-institutional users of Chromebooks to see that there is a market for them. (I had one of the original demo units and really liked it.) I can see why Apple would want to get a piece of that market.