They absolutely serve purpose in nature, they are a significant food source for bats and many other insects and males are pollinators.

They need blood to procreate so the method in the post does exactly what you are asking for

Many species of mosquitos are reliant on blood for reproduction. The females utilize a “blood meal” for the nutrients for laying eggs to be fertilized. Additionally, it is the female mosquito bite that transmits diseases like malaria.

Bats eat mosquitoes so we be killing off bats food supply. So just get bats and solve your mosquitoe problem.