1 - http://en.wikipedia.org/wiki/Google_Maps#Acquisition
2 - http://en.wikipedia.org/wiki/Android_(operating_system)#Hist...
Google does what's best for Google. Google doesn't do what's best for its users. Its users aren't its customers (its customers are advertisers). If Google does something that appears to be good for its users, it's because it's good for Google as a company.
Furthermore, when Google acquires a product/company, it does not do so because it wants to further that product/company's goals. It does so because it wants to further its own goals.
Basically, Word Lens is joining the Google Translate team. But that does not necessarily mean the Word Lens functionality will be put in the iOS Translate app. Google will do that if they think it's good for Google, but I would not be in the least surprised to see them reserve that functionality for e.g. Android or Google Glass.
Edit: Whomever downvoted me, care to explain your reasoning?
Unlike every other for-profit business in the world?
(I didn't downvote, BTW)
For most companies, their users are their customers. Doing right by their customers means doing right by their users.
But Google's customers are their advertisers, and their users are their product. Facebook and Twitter are the only other examples I can think of of companies with massive user bases who consider their users to be their product (except Facebook and Twitter are relatively focused on their core product, whereas Google seems to be trying to do pretty much everything under the sun).