Although Mongolia has no direct connection with the sea, there are many lakes in their country, large and small, and there may be some oil reserves in the lakes that we didn't imagine, so it is possible to set up a navy at this time to exploit the resources inside, which also brings certain convenience to the country.
Moreover, this mongolia navy has only seven soldiers. They are driving the only warship in Mongolia and berthing on the Kusugur River, 2000 kilometers from the sea. Moreover, these Mongolian soldiers have not participated in any military mission. Their main task at ordinary times is to transport the wool and leather of Mongolian assets to Russia for trading.
Therefore, I think Mongolia established its own navy for various reasons, not to say that it is useless, but also has its own certain benefits, not only in terms of income, but also in other aspects. They have the right to form their own navy. Can bring benefits to the country, why not?