Out of curiosity, I went onto Twitter and tried to post a link with one of the similar sites as JSFiddle. It seems that CodePen URLs are still allowed. This seems very strange to me, as unless I'm missing something, CodePen has the same inherent faults as JSFiddle.
Twitter clearly has taken the easy way out here, and instead of addressing the problem and tried to tackle it, just blanket banned JSFiddle with no regard to their users, or to the variety of similar services that provide the exact same functionality. If I was a crypto miner, I would simply copy paste into CodePen and continue on my way.
Any website can have a miner, outside of some safe content only sites. It may as well be, that in some distant future, users of social sites will be able to link only to other pre-approved major social sites.
You can't even link on most of these websites without going through some intermediary URL forwarder.
Twitter clearly has taken the easy way out here, and instead of addressing the problem and tried to tackle it, just blanket banned JSFiddle with no regard to their users, or to the variety of similar services that provide the exact same functionality. If I was a crypto miner, I would simply copy paste into CodePen and continue on my way.