Because some other members seem to think being tracked can result in privacy issues:
The reason behind not recommending the single address for faucets is the "dust transactions" (a very small BTC payments). So after some time your BTC address would contain a lot of small transactions and when you decide to move them you will be surprised with a very high transaction fee. (this was issue in the past when most faucets were sending the payments directly to your wallet ... but using micropayment platforms like faucethub will minimize it).
You can safely use single address for faucethub (as the hub will unite your small rewards and send them to you in bigger chunks) ... still not optimal but better.