Well that works if you're a startup in one timezone with no teams depending on your service. If you work on a larger company, it's quite possible the sun never sets on your project (west coast, east coast, Europe, India, Australia or SE Asia)

If the sun never sets on your project, then you probably don't want to shut it down because you're using it 24x7.

But since a Lambda is a program, you can make the criteria as complex as you like.

Tag it with "shutdown=non-biz-hours", and "timezones=UTC-7,UTC+0,UTC+5:30" and your shutdown script can figure out when it's outside of business hours in all of those timezones and shut it down.

If the sun never sets on your project, why would you want to shut the instance down?

One reason would be that the savings is worth the increased latency. Depends on the situation.

I'd only do this strictly in dev or qa. Remote teams can always spin it back up if they need it on a wider schedule.