Lots of faucets are using a service called Microwallet.org as a place where payments are stored before being sent to you.
Microwallet.org is a micropayment cache. Various faucets are using this system for different reasons.
When a transaction takes place on the Bitcoin network it is sent to the blockchain where it is confirmed (this takes time) and a transaction fee is charged. With Microwallet the owners and operators of faucets send coins to an address and they are stored to later be divided up “off the chain” immediately.
This allows for faucets to send a message to the Microwallet.org site saying that you have received some Bitcoin and they move it internally from the faucet address to your Microwallet.org address. Once you’ve reached a threshold the coins are avaliable to you as an end user to be withdrawn which is when the transaction goes back on the blockchain.
By using a site like Microwallet.org it is easier for a faucet owner to send you micro transactions and saves you the fees by bundling up transactions as well.
What makes this such a cool service is that once you’ve reached the withdraw limit you don’t have to do anything. The coins are automatically sent your Bitcoin wallet address, plus you don’t have to do anything to actually get your Microwallet setup. It automatically exists when you use your Bitcoin address on a site that supports Microwallet.org
Microwallet.org is completely trustworthy, the developers are active on various platforms and the always payout on time. As you are using the various faucets that I am reviewing many of them are powered by Microwallet.org.
While Microwallet.org isn’t a true wallet but more of a temporary storage space for small transactions it is completely reliable and home of several Bitcoin faucets payouts.