If all you're doing is basic web stuff then sure you can do it in Lang du jour but even after a decade go doesn't have a competent xml library for example.
Time to market is killer. Python buys you time to determine whether your product is even worth building. Deployment sucks though.
e: I literally could not have written the services in my current role in a language other than Java or Python without replicating 100kloc libraries. Java would have required a bunch of work to integrate with the other services we had. So: python. If that costs me an extra $1k/mo for servers but gets us a customer paying $100k a month, was it wasteful?
