The cost savings are not the main advantage of AWS Lambda compared to EC2 (AWS recently announced EC2 will bill on a per second basis and a minimum of 1 minute). Instead, I'd argue that the programming interface, managed operations, and scalability are what makes it a better tool for these types of tasks! I'm looking into running other more general computations on Lambda right now as part of my PhD! (stay tuned for more soon). Until then, check out ExCamera (https://www.usenix.org/conference/nsdi17/technical-sessions/...) and PyWren (https://github.com/pywren/pywren).