Cryptocurrencies have always had a problem with user interfaces and user experiences (UI/UX). When you send Bitcoin or Ethereum, not only are the wallet interfaces usually not intuitive, but there are so many variables you need to consider. For Bitcoin, you need to think about fee rates, whether you want to subtract the fees from the send amount, and whether you want to use change addresses. For Ethereum, when you're setting fees, you need to consider both gas limits and gas price.
Once a user sends a transaction, s/he then needs to wait quite a while before it appears in the receiver's account. However, the problem is that there is no guarantee that a user's transaction will even go through. If the transaction fee was set too low, the transaction might be stuck in the mempool forever. To make matters worse, there is also no guarantee a transaction will NOT go through. So if you sent a transaction to someone but it never gets confirmed, it's also risky to send another transaction since your first transaction could be confirmed eventually causing you to double spend. Of course, there are ways to solve the "stuck in the mempool" issue such as with Bitcoin's replace-by-fee feature, but these solutions are far from being easy to use.
Steem is the first blockchain where you can build apps on that don't even feel like you're using the blockchain! Transactions are fast and, very importantly, free. This allows a user to interact with the blockchain like they do with normal applications today. These properties allow Steem to host a social network which relies on low latency and free reads AND writes to be successful.
No other blockchain comes close Steem in terms of its UI/UX. Think back to CryptoKitties and how it was a total pain in the ass to use. The app easily clogged up the blockchain and people were paying massive fees to only get their transactions denied because they arrived too late. Besides the chance to make a bunch of money, CryptoKitties definitely wasn't a fun experience.
For this reason, I believe Steem is an underappreciated but revolutionary blockchain. People are not hyping it up on the major subreddits and Telegram groups. It's not in the top 10 cryptocurrencies in market cap. But in terms of true usage and value, Steem is, in my opinion, in the top 5 right now. Steem is the brainchild of blockchain genius Dan Larimer. To fully understand how Steem accomplishes all this while still being decentralized, please do read through its whitepaper.