It’s very much in a country’s interest to make it as easy as possible for tourists to come in. They spend money. They don’t expect much in the way of services from the government.
Letting people in to work is much more controversial. They take jobs that your citizens might like to have. If you let too many of them in, they create an employer’s market, which is likely to drive down wages and benefits. It’s likely to be popular with people in your country if you make it harder for people to come in to work.
Same reason the U.S. doesn’t let tourists work. That makes it very easy for someone to come in illegally and it makes it more likely that they will overstay their visa and reside here permanently.
Most of the non-EU students, I met when I was studying for a year in France who worked were working under the table.
American students are elligible for a four month working visa in Ireland and (IIRC) a six month working visa in the UK. These visas are part of a reciprocal agreement both governments have with the US. Elligibility depends on whether you are in higher education or not.
Sorry to nitpick your nitpick, but the 1st sentence here is semantically innaccurate in a few respects. The Scottish Government is officially called that as of last year, except in matters relating to the Westminster act that founded it. Scotland is officially a nation*, not a region, and it has a parliament, not an assembly. Having said all that, neither the Scottish Government or the Parliament have or claim any power over immigratoin and border control. And if Scotland is not a nation, then neither is England, since the 2 have the same constitutional status within the union.*
** Please don’t raise here the issue of Scotland having arguably a higher status within the union thanks to the West Lothian question - that’s for another thread.