"Channel-switching" is referring to the wireless channel. Modern wireless routers will "intelligently" select a wireless channel to communicate over, taking into account features of their environment. For example, if there's high competition with other wireless transmissions on one wireless channel, they'll switch to a less contested one.
"Promoting network health" is a bit of a nebulous thing to say about a home network served by a single router. As a pragmatic observation, rebooting a router can solve a variety of problems it might be experiencing. Most home users can't distinguish local machine problems from problems with the network, and automatic periodic rebooting of the router probably prevents a lot of support calls. If you're happy with rebooting your own router as and when you see fit, I don't see why you shouldn't turn this feature off.
This thread is for asking any questions that might seem obvious, tangential, silly or what-have-you. Don't be shy, everyone has holes in their knowledge, though the fewer and the smaller we can make them, the better.
Please be respectful of other people's admitting ignorance and don't mock them for it, as they're doing a noble thing.
To any future monthly posters of SQ threads, please remember to add the "stupid_questions" tag.