There's been loads written on this subject, think of the difference as an exchange fee.How is it that the amount of points to stay at your home resort in the season that you bought is higher than the number of points you are given to use? For Harbour Lake I could not use my points to stay at my own home resort since the points allotted to me are lower. They (Marriott) should really give you the same amount of points that they charge for your resort in the season that you purchased.
1) As a rule of thumb: Don't elect for club points to go to your home resort, use your week for that.
2) It varies a lot depending on the resort and seasonality. There are a few locations where you can get a week in the season you own for less club points than you get from electing. The club points for election are an average of the points for that season less the fee aka "skim".
3) If you go Sun-Thurs the number of points required is a lot less than Fri/Sat. Combining a points booking with a week stay is a great way to get value using points.
4) Trading in II can be a better option, depending on where you are looking to exchange into, rather than electing for club points. You can't book a view, so if that is important you can book a view using club points.