Question

How can extinction of snake affect us ?

Answer 1

we can get saved from their bites which are poisonous and kill human beings

Answer 2

Extinction is the termination of an organism or of a group of organisms, normally a species.
First, cases of musophobia — the fear of mice and rats — would ramp up considerably. The population of rats and mice would suddenly hit up and no one would be there to eat them because we one part of good chain is removed.
Second, snakes are also prey for some animals we generally like having around, such as all species of cats, coyotes, mongooses and even other snakes. A big snake-sized break in the food chain could negatively impact a variety of other animals.
Most important to humans is the role of venom produced by snakes, as well as other venomous creatures, in the development of medicines. Diabetes and heart disease medicines have been derived from snake venom, which is also being used to develop treatments for autoimmune diseases, cancer and pain.

Hope it helps ..!