If 5ghz provides a good signal throughout the entire home then separate SSIDs is good way to force a client onto a single band without the worry of signal strength running weak.
Is that better and more stable? That comes down to the most effective arrangement for your unique environment and your usage needs. And without lots more detail of your physical environment, topical layout, emissions environment, clients, client usage patterns, etc. only you can assess whats better or more stable.
IMO, the typical home user with the typical array of consumer devices doing typical home network activities is just wasting their time using anything other than single SSID in auto mode for a dual band setup. But, hey, who doesn't like to tinker