I went through this process before COVID, with the intention of travelling to Dubai, and they knocked back my request about 10 times for spurious reasons, and were adament that I couldn't enter Dubai with a single pill more than was required for the duration of my time in Dubai. Which of course is completely unrealistic - I'd need some for travelling back, and a small buffer because of flight delays or whatever.
Honestly, travelling with certain medications is a major PITA.
One-time cures may be a sci-fi dream but they are highly desirable, as anyone who needs regular/prophylactic treatment for any severe ongoing condition knows.
International travel is a minuscule thing to give up if you get effective depression (or pretty much any chronic condition) treatment in exchange. Heck most people can't justify the expense of international travel in the first place and the number of people who do it regularly for work and have depression is very small compared to the number of people who have depression. Practically nobody is going to let a chronic condition that affects their daily life go untreated because there's a short list of countries they can't have that treatment in.
A much bigger issue is as pointed out by harimau777: prescriptions often don't get filled on time and sometimes not at all. Plenty of people run out of pills on holidays and have to suffer withdrawals, with suicidal ideation and actions being one of the symptoms of acute withdrawal from benzos.
Daily medication that requires a prescription is a huge problem for people that actually have to take it. What if they can't afford it at some point? What if their physician changes and the new physician doesn't want to prescribe it?
Why are we even defending daily medication? If there is any possibility of a permanent cure, obviously that is a much better choice of treatment.
What does conscientiousness have to do with it?
You might need to travel or transit through a country which prohibits carrying them. Now you have to cancel the trip or go without the medicine.
> by all means come up with a one-time cure on your own
This is not helpful. People have the right to ask questions without being asked to devote a lifetime to develop some arbitrary authority (which would then in any case bias them to look for positive results).