I think it is wrong because AWS doesn't provide function. More correct would be Function Caller as a Service
How about "worker queue" ? because it is exactly what is it. Obfuscating the details is silly. There is nothing new about the technology. It is only marketed as new (which is reflected in the pricing).
Even that's tricky, because it's also Backend as a Service BaaS/MBaaS at work, various frameworks and other solutions, etc.
It can power a front end. It's like a micro container as a service.
As long as you don't mind 3s startup latency, or 200ms hot path latency?