It is not. Under $100/year in most states.
> and probably has tax consequences.
It doesn't. The LLC has no income (assuming you're not renting that "decoy house"), so there's nothing to report to the IRS.
> doesn't even really solve the problem of having to give your address to someone if you want anything delivered.
That's what a PO Box or rental mailbox is for.
Just keep in mind that you won't be able to hide the fact that it isn't your residence from the data brokers or anyone else who demands a "residential" address and is willing to spend a few dollars verifying that.
