2. What is special about coinbase that almost all the website are ranking it to be the best crypto trading platform?
I usually use Binance for trade but i have also experience about Coinbase, Bittrex too. Every exchange have their own specialty although i never thought that Coinbase is better than Binance. For beginner i would like to recommend to start their trade with CEX exchanges like Binance, Kucoin cause DEX exchanges are more complicated use than CEX. No doubt that coinbase is trustful exchange but there is not much special about coinbase it's just hype nothing else. Most people like because of there affiliate program for new sign up users.
when i was a newbie my first experience on trading was on decentralize exchange and it was on etherdelta which was make it more even harder but this is good because you can master any exchange easily later on if you start with the harder ones . i also dont thought that coinbase was good because they rank number 1 but its not the ranking that really matters but its the user experience . maybe coinbase rank first because they are multi purpose ( they have a crypto wallet and a exchange )