The only way that a user could take advantage of multiple accounts is that they would be able to get more faucet requests and potentially rain from chatting.
As in the formula DogecoinMachine posted, as well as the faucets investors also pay for referral income. This is the most common reason people cheat with multi-accounts. Self-referring has a far higher potential gain than faucets.
It's very bad for players to commit faucet abuse or referral abuse as you mentioned.
What is worse is when the Crypto-Games.net casino owners steal coins from players for breaking a rule about having two accounts that they were unaware of.
Shame on crypto-coins thieving owners for stealing my 470,000 doge coins.
Warning to all players. Do not support sites that steal from players