Why is it that it's the Treasury Dept restricts travel to Cuba?

I was reading about Jay Z and Beyonce’s trip to Cuba where they mentioned they got permission from the Department of the Treasury. Why that Department and not the Department of State?

Because Treasury embraces Customs, and Customs has a lot to do with controlling entry to and exit from the United States.

I don’t know all the political details but, as it has been explained to me, the restriction isn’t travelling to Cuba… it’s spending money or doing trade with them (with American dollars or goods I presume). Which I guess is more of a treasury thing? However this sounds highly suspicious. Lots of Americans travel to Cuba every year by going through another country first with few problems, and without getting permission.

But anyhow, the main fact remains that the embargo against Cuba doesn’t actually say “No Americans allowed on Cuban soil ever,” it just aims to make it logistically impossible/difficult to go straight from America to Cuba or vice versa.

It says here that the State Department is authorising tourism to Cuba.
So it seems you can get a permit from EITHER State Dept or Treasury .

There are more interesting rules.

Companies cannot do business with Cuba. This has dinged Canadian companies that are subsidiaries of American companies, including banks and even IIRC, a company that made locomotives.

Of special intrest, IIRC, was a mining company in Saskatchewan that has a deal to work a mine in Cuba; since the USA stilld does not recognize the validity of Cuba nationalizing the mine from the original owners (resident in the USA?) teh executives of that comany are apparently barred from entering the USA.

This is the crux of the embargo - (a) the USA does not recognize property “stolen” from the original owners in 1960, and (b) the settlement of the Cuban missile crisis was that the USA promised to not invade or attack Cuba, but instead put in place an economic embargo in an attempt to cripple the country financially. (IMHO Cuba did not need the USA’s help to do that).