This post if for the players not the DMs out there. Empty rooms are a feature for you to exploit. Yup they aren't just the DM wasting your time. Take advantage of those empty rooms.
Pester your DM for information about the empty room, there's something in there and you might just find it if you look hard enough.
Rooms are empty because nothing in the dungeon has the resources to keep this room secure. Is it worht it to you and your fellow players to secure the room?
Are there any hiding spots in the room, any nooks where some loot can be stashed? The locals might be used to this room being empty, those coins you boosted might just be safe here in this room instead of weighing down your faithful henchman.
Have you just had a big fight and the party is exhausted, is it a good idea to stay where you just had the fight to bandage up and rest? Wouldn't it be smarter to go back to that empty room and recover there?
Why are you and your buddies always kicking in doors and having a fight on the baddies turf? Knock on the door, make some noise and have the baddies come fight you on a battleground you have readied, you know, in that empty room.
Empty rooms and the passage leading through them offer a means to corcle arroudn foes and for the baddies to circle around you. It's a lot harder for monsters to circle you or simply wander up to you unnoticed of you take time to bar doors and place alarms in those handy empty rooms.
Talk with the folks living underground now and again. They might not want to talk with a band of kill crazed dungeon looters in their living room but they might be convinced to have a meeting in the empty room down the hall.
Those empty rooms are territory for you and fellow players to exploit to your advantage because the monsters/baddies don't have the time and resources to exploit them.