Does it mean that only immigrants who obtain permanent residence can obtain the benefits of this country?

Basically the answer is "yes"

But in fact it is not. If you have a normal student, work permit, permanent diplomat, etc., long-term residence, yes The state provides equal national welfare.

As for the "free" medical insurance you mentioned, it is actually not "free" for anyone. It is usually paid for in some way. It’s just that in countries with better welfare, those who are too poor cannot afford to pay the fees, so the state subsidizes them.

If it is just for medical treatment, you can buy medical insurance before traveling to that country, which can achieve the same goal. . . .