You may be spending too much time with the micro confusion "they" like to "sell" with.
Sounds like the apartment will be selling for $1,000,000 plus maint. (assuming 2 weeks not sold each unit). If that is not 10 times the value...
Timeshare can routinely be purchase for 5-25% of the original price after a year or two into the project. Resales are highly illiquid and can cost commissions of up to 50% on the lower value mentioned above.
Be also aware that trades often can cost $50-125 each (do not know the Marriott charge). Note that seasons are very impactive on costs and trade availability.
I have read on this board of one person who is happy with their timeshare and know several people with horror stories. You figure....then run!