Yep. It's good old fashioned webhosting. Drop your files in the amazon equivalent of ~/public-html/ . If it serves your needs, it's not a bad thing, but it's hardly revolutionary.
A consequence is that you really want to terminate quickly and use little RAM. If your JS function terminates in 110 ms and get billed for two 100 ms units you might be tempted to switch to a faster language (or ASM what you can) to save half the bill. Webhosting doesn't have that dynamic.
How do I get "old fashioned webhosting" to automatically scale-out and scale-in?
How do I do all that and get per-100ms CPU-time billing?