You often want to control brightness and possibly color on light bulbs, and it's good if that can be integrated with other systems so you can have central control and automation. Wifi may not be the best way to connect, but it's reasonable.

With an air filter, do you ever want to control it? Naively I'd think that you'd want to leave it on unless you're going to be gone for a week or more. And even in that case it's probably easier to flip the switch.

Would it tell you when it needs a filter change? Would that actually work better than a calendar?