App Engine seems to serve exactly the opposite of its stated purpose. The idea with scaling is that when demand increases, you allocate more resources.
With appengine, when demand increases they turn off the server.
It's really the only platform you could pick that's guaranteed not to scale.
True but that is for the free GB transfer per day. They probably wouldn't ever make any money if they took the hit for everyone's spikes. Otherwise you'd just offload all heavy spike situations to AppEngine. If you pay for bandwidth you get past the quotas.
I agree though in demonstration it seems silly. They shouldn't even have a free plan because all of them end up like this, bad perception.
When demand increases they turn off the server until you pay for more. It's not a charity! If you want to just serve static HTML, put it somewhere cheap like nearlyfreespeech.net
As an aside, where's the cost benefit in nearlyfreespeech.net? After transferring a hefty 10,000GB you are still charged $0.20/GB, while (say) linode charges you $20/200GB = $0.10/GB from the outset.
With appengine, when demand increases they turn off the server.
It's really the only platform you could pick that's guaranteed not to scale.