"The one in my bedroom, admittedly, is turned on every night, because FM reception is awful in there."
Reception is very unpredictable on either of my two DAB house radios - yet they both receive Wrotham FM with no problem. They are all connected to the same wideband distribution system plus masthead preamp. I only switch momentarily to the DAB channel for Classic FM when I want to know the title of a piece of music. If they used the data subchannel on FM to do that then DAB could be ignored completely.