Because the authorities have control over all of our assets. In the event of a fraud or a crime they can freeze them even confiscate them.
But noone has that control over your bitcoin, for better or worse
Again, it seems the primary use of bitcoin is to facilitate fraudulent activity.
For a normal, law abiding citizen, I cannot for the life of me see how it is practical or feasible to use Bitcoin as a store of value and to pass this asset on to my next of kin. It's just not fit for purpose.