My bank allows you to deposit a small amount of change each day. I don't see why I cant go every few days and depostit 5-15 dollar coins -- but I cant say with certainty how much I can deposit each day.
Others have said the coins are good for tips. I agree, I have used them in airports to tip luggage handlers or skycaps, though I have to frequently explain to them that it is a $1 coin.
My best use for the $1 coin is paying a toll at a bridge, tunnel or turnpike. IMO, I think the toll collectors sometimes prefer the $1 coin. I've never gotten any kind of negative response when I hand them several $1 coins.