Honestly I think the spark is the better option for people new to the sport.
Consider a person who decides they want to try the sport but has zero mechanical ability or knowledge of skis. Sothey buy a used 2 stroke for $1k off craigslist. The likelihood of that ski running flawlessly is slim. They take it out and have reliability/running issues so take it to a local shop. A lot of shops are shady and will end up having that person blow 500-$3k on carb rebuilds, pump rebuilds, engine rebuilds, etc etc. Now maybe it runs great for the summer but issues start again a year or two later.
That person probably gets turned off completely from the sport and goes to sell the ski to realize it's worth $700.
If they had bought a spark initially they are covered under warranty and are likely fairly happy with it.
This theory also helps me as it keeps these newbies from buying the old 2 strokes so I can grab them lol.