The power in question is the president's power over the executive branch of government, e.g. the department of Justice. If the president orders it, the department of Justice could choose to feign ignorance and simply not fine any offending parties under this law. Obviously this is an immense power that should be wielded with the utmost care but at this point I'm not sure anyone cares.

I think the idea is that Trump wields enormous (unprecedented?) control over the members of his party, and thus effectively controls both houses of Congress for at least the next two years. I assume he'll quickly get whatever legislation he wants sent to his desk for signature. I'm wondering how long it takes before the Senate invokes the "nuclear option" on what still requires a filibuster-proof majority to pass.

Biden will probably not enforce the ban (no fines) and Trump will likely continue that non-enforcement, essentially nullifying the will of Congress and judgement of the court.