A single server not breaking a sweat means that this can be handled by a middling VPS that is breaking a sweat, and that load only lasts a few hours. That means that it's stupidly cheap for Google to provide for a few hours of load like this, and the ability to absorb a huge spike on a cheapo plan is supposed to be one of the main points of cloud hosting.

Lots of people make cool stuff without dotting all the i's. That doesn't look bad on them - it just means they're doing the hard stuff and skipping the grungy parts of a project until it seems necessary.