"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.