The issue with this is how much most faucets are paying. The majority are 1 uBTC or less. This means 100 satoshi.
0.001 BTC is 100k satoshi. So it would take 1000 captchas to get that assuming they were all 1 uBTC. Most people aren't going to go through all that work for it.
Faucets are meant for lazy people who don't have any qualifications to do freelance jobs. Therefore, the pay rates will be much lower than that of the other jobs.
