Random "hey" texts from girls you're pursuing. Sorry guys!

Not every girl does this, but I've met a few recently who will randomly send me a very short text message with nothing more than "hey" or "hello." The last time I got one was this morning, from a girl who had flaked on me the other day. My texts are always very to-the-point, whether it be sent to a friend or a love interest, so I've always found these kinds of messages off-putting. When I receive them, I usually try to mirror the other person, responding in kind with some something like "hey there" to let them lead the conversation where they want. This morning, the conversation ended up being nothing more than "i'm at work, you?" I figured she was inviting me to make a move, so I said "so when are we finally going on our date?" I'm now waiting for a response.

All girls are different, but is there some kind of subtext that I'm missing when girls send these generic greetings over text? Are they just wanting to small-talk, or is it some kind of way of getting my attention? How do you tend to respond when you get similar messages?