And because it's IKEA, they understand the "spouse acceptance factor" well. TIMMERFLOTTEs may be cheap in construction, but look decent enough, blend well (I have a dozen of them stuck around house, mostly next to light switches and nobody notices), and most importantly, the local display is only on for two seconds, and only when you press it.

They have a more expensive variant looks more like desk alarm clock, that also measures particulates and carbon dioxide (and tells time), and that one can stay always-on (and act as Thread router) - but they wisely remembered to add remotely triggerable switch to switch the display off, too.