There's definitely a market for those boxes, else they wouldn't sell any. It's quite a bit more trouble to build your own cabinet. I probably saved about a thousand bucks by building my own, but what I saved in money, I probably spent in time and sweat. No one should knock anyone for deciding to spend money rather than time. If you can work and make more money per hour than you'd save by doing the work yourself, well, simple math suggests that's a good plan.

Sorry to see your root rot problem. Doesn't look like a big yield, no, but if you learned what not to do next time, well, that's a pretty big positive! Hopefully your next grow will be what you originally envisioned.