Why do countries have visa system?

Question

Why do countries have visa system?

Answer 1

Every country has the right to decide who can and cannot enter.

And, contrary to another answer, no country actually makes a profit on visa fees; the US fee is used to pay for the worldwide computerized visa system, rather than expecting US taxpayers to shoulder that expense when they get no benefit from it.

Answer 2

Visa system allows a country to screen persons that can be allowed entry to their country.  It is also being used to discourage applicants and generate income by pegging a high price for the application fees but denying majority of the applicants just like what the US Embassy is doing now.

Answer 3

to control entries within the country, otherwise anybody and every one would enter the country......the country not having visa could get all immigrants in the world, who in turn , would have to be fed,lodged,cared for, it would cost a fortune,

also today with all the attacks against some countries, you could not control who would come in and be a threat to the country itself, things of that nature............