Triple the length means triple the pressure... It takes a lot to move beer through a narrow channel. At some point the fittings appropriate for plastic won't handle it.
If you're hankering for a jockey box, find some way to adjust your budget and swing the proper equipment. There are used set-ups and there's surplus stuff occasionally. Don't cheap it out...your beer will thank you. I've never regretted spending a little extra for something that works as it's supposed to rather than being a works-pretty-well solution that requires constant baby-sitting...and I'm a cheap SOB.
And, yes...the biggest draw-back is heat conductivity. You have to chill beer instantly going through the tubing. Plastic is an insulator, not a conductor.