Gold is compact enough that you can pack a fortune in a suitcase by most people's standards. $90B is a lot of money though so you are talking 700 metric tons which is a lot.
But the total amount of gold seized worldwide is much smaller than Bitcoin (using today's spot prices). There is a popular argument that Bitcoin is better than gold because it's harder/impossible to seize, which is simply not true.
Also, I meant to share this article, not the one linked by this post: https://illya.sh/threads/multiple-governments-have-seized-bi...
It's on the same topic, but more detail.