Why do governing countries often maintain control of exclaves (like gibraltar and kaliningrad)?

i do not know if this question has options, but a main impact of the federal reserve act of 1913, which created the federal reserve bank, was the international use of the u.s. dollar, which soon became the world's leading currency - particularly during world war i, since many nations around the world asked the united states for money.

no every country is held to the same degree as others just some member countries such as the usa and germany are more economically sound so the need to show there support to all others