I'm curious to know which websites offer the most reliable and secure platform for earning bitcoins by watching videos. With the surge in popularity of cryptocurrencies, it's become increasingly attractive to explore alternative ways to accumulate digital assets. However, the internet is vast, and with so many options available, it's challenging to distinguish between legitimate and potentially fraudulent platforms. Could you elaborate on which sites have a proven track record of paying users in bitcoins for their viewing time, while also ensuring data security and privacy? Additionally, are there any specific criteria or features that one should look for to ensure a safe and rewarding experience?