Firstly the the Egyptian Islamic Advisory Body is a national body set up to make laws for only Egypt based on their interpretation of the Islamic laws.  Its decrees do not affect other Islamic nations and it is not even binding on the citizen of Egypt because it is just an advisory body.

The term haram in investment is majority connected to gambling and paying interest on loans. If crypto trading is a sin then every form of buying and selling is also haram. In crypto trading just as in any other trade, you buy a coin to sell to another trader and make a profit. It is not like gambling where you transfer your money to another person without receiving any asset. But in trading, you have to buy an asset and sell it to make a profit. It's also the same thing as going to buy some oranges and selling them later to make a profit.

Some Islamic scholars have also claimed that crypto trading or investment is haram because it is speculative. But many Islamic nation holds large gold reserves which is also a speculative asset.