Sure, it might be worth it if the original (triple) drivetrain if of high enough quality to resell on eBay. If the parts are good quality and in decent condition, you might make enough money on eBay to pay for the conversion. I tried a 1x9 on one of my bikes but found that it was actually more trouble to ride than my doubles. The reason is that there are a lot of hills where I ride, and I often switch between the big and small ring without having to shift cogs. With the 1x9, I was having to shift up and down through a lot of gears when going from a big downhill to an uphill, rather than just shifting the front derailleur.