The challenge is engaging with external orgs. They will send you office docs and it creates friction when they cannot be reliably edited and returned. Even just opening them can be unreliable.
How do you think currencies are established? By accepting chickens and cows in lieu of legal tender? That’s precisely the meaning of legal tender. This is the exact analogue thereof: information is required as value is required, information and value are required in a mandated standardised form, other forms are rejected a priori.
Sure, the government could force a format change if they really want to.