To one degree or another most boats have self-tacking mainsails. In some conditions the traveller position needs to be adjusted after each tack, but by and large most mains will be fine with just tacking over.
On the other hand, jibs that lap the mast, shrouds or a stay, need to be tacked over. With most sloop sailplans, the normal sails that are used are a mainsail and a genoa of some size that will by definition lap the mast. So the first thing about a self, tacking rig is that it can''t have a jib that laps the mast. Typcially this means designing a boat with a larger mainsail and smaller jib than might otherwise be normal (most times these are also typically fractional rigs to allow the rig to be easily powered up and down but not always.)
There are several ways to make a jib self-tacking. Historically, the jib would be mounted on a boom and might have a traveler just like a mainsail. The Europeans seem to like self tacking jibs a bit more than Americans and they lean toward a transverse tack that the jib is sheeted to. (Look at the Hanse website to see what that looks like.)
The reality is that once you are willing to live with non-overlapping headsails, (or even minimally overlapping headsails), 110% or so it is gets very easy to tack a jib. (I can tack my 110% very easily single-handed without using a winch handle.) So I am not sure that a self-tacking headsail, with all of its clutter, cost and reduced efficiency really makes a lot of sense in most applications.