Good questions actually, I`ll give an answer a shot.
The Winter Village sets have proven to be very popular, and thus excellent investment sets. Previous releases were available direct from Lego through the Christmas season, and more difficult to obtain/not directly available throughout the rest of the year (that`s the case with some, not all of them). My point here is that in this time it was possible to flip the set(s) for a quick profit, but time has also shown that the value of these will increase dramatically more with each passing year.
Bottom line, these are great sets because Christmas isn`t going anywhere, and eventually they do have to be retired. Means that they are very safe/excellent long term holds, yet they also have the ability to sell at a higher price in the short term as well depending on availability. In the case of Santa`s Workshop, I`d buy literally as many as you can, it`s excellent for the price, and paired with the Workshop set will continue to be very hot items each year. The limit of 1 is clearly allowing a small profit bubble to form over the set as well at the moment, because some buyers understandably want more than 1 (for gifts, themselves, etc.) and that is difficult to do directly.