You might want to keep it this way! I have read in several magazines that at present there is no tool that can guarantee a successful deletion of data on SSDs. So if you plan on selling your SSD a few years down the road, make sure that you never had personal files on it, unless you want to share your little secrets (which we all have).
Hard drives are so cheap these days that I always tell people planning to resell their computer that they should remove their hard drive and either sell just the chassis or bundle a new hard drive with it.
As for reselling the SSD on its own, don't make me laugh. The depreciation of the value of the drive and the obsolescence of the technology at the point at which you sell it will hardly make it worth your while. I wouldn't advise anyone to buy a second-hand hard drive anyway.