An acquisition would only make sense if they had relevant patents to purchase, which they do not.
Not always. While it is highly likely that Google could hire (or already has) the talent to build the same thing, acquiring a finished product and the talent that built it can be cheaper and faster than DIY. But yes, having a patent would make a deal even sweeter.
Don't underestimate the amount of work, expertise and experience required to arrive at word lens, to date I've to yet to see this technology duplicated elsewhere. Google has acquire hire before recently with milk inc, I don't see why they can't with this team.
This. Wordlens is computationally intensive and required a significant amount of GPU knowledge to get working in the first place, and then a couple revs of the iPhone before the hardware caught up. Otavio has some serious graphics chops that made the product possible.