Dunnomuch

Hi all, Obviously new to this hence the handle but my question is how useful is a metal detector indoors? Just picked up an old house and the previous owners were old and passed away, so the children auctioned it off. I want to do some searching for silver and gold bullion, coins, jewelry in the walls, etc just in case there is anything stashed away. Seems to me that there are so many different ferrous materials in a house that you would be getting a ton of noise and chatter and might not be the best use for the device. My friend who is in construction suggested a thermal camera (for walls, etc). Any advice would be appreciated. BTW, currently looking at the MineLab Equinox 600 but also considering 800 for the gold setting. Should I save my money?