I don't see conceptually the difference between the first and the second example. You're still executing two distinct actions, first being the waiting for x amount of time?
It could be issuing a command in the same way you do the first, but probably most lights just support switching them on/off right now, and won't take a delay argument.
So, if you can't just do the same you were doing, how do you do it? If there's some kind of local support, you can issue a delay command to some device in the network that will switch the lights on, but you still need to be able to control that action as the user might want to cancel or adjust the delay too.
If the execution need to happen remotely because there's no local support, then you don't even know that you'll be able to reach the device in 5 minutes (Internet down, router not letting random connections in). And keeping this request queued needs some infra in the server side too together with the necessary APIs to allow adjusting and cancelling requests.
Where is the hard part?
There is storage going on already
I'm pretty sure there is some form of local support, at least for Google. Whne I last used it you had to choose a speaker that automations executed from
The AI feeds the action queues, and another isolated component performs the actions, including delays and follow ups.
It's not a fixed amount of time. What if you rewind in the song a bit to catch something you missed in the lyrics?
I think this highlights that AI assistants are not really "I", they are good at doing fuzzy, hard to specify things like understanding speech, but there must still be an engine behind that interprets the text and transforms it into execution steps, and that must still be done by developers so it will be limited.