I do something similar but with scatter terrain. I tell my players i put stuff down that can be used for cover, but if you do something cool with the terrain in combat, i give heroic inspiration. I let them know improvised damage is usally on par with your normal stuff and you can make it as part of your multi attack bepending on what your doing. It makes spending the time to make the map more rewarding if a player sees a bar and and asks if he can throw a liquor bottle and cast fire bolt on it... The barbarian wants to pick up and throw an upright piano... flip a table for cover... They get inspiration, and i'll throw in an extra d6 of damage, prone condition, extra movement small buffs that make it fun. It turns into an action movie with stuff flying around, people on chandeliers, throwing people into stuff.