Twitter doesn't really understand what made it so successful. What did it start as but a blogging service limited to 140 characters? That's why they are so resistant to change. So they're looking for a company that has a user experience that the trust, not just spinning up a crew to spit out a feature.
I'm a customer of a company where I recently requested a relatively basic feature. They said they were putting together a team to implement it. That was bad.
Twitter, on the other hand, seems to need to buy a company in order to improve a basic feature. That's horrible!
What's up with management culture in tech companies!?
Buying a company is often a very efficient way of getting something built. The price may be lower than you think and they get a team that's already worked together and isn't bogged down by internal Twitter politics. If the executive running the acquisition can protect the team from those politics they can get something built faster than they would otherwise, and at $10m Twitter revenue per day, getting something out the door faster has a lot of value.