The question is about deporting illegal immigrants specifically, i.e. people who are in a country in violated of its immigration laws.

I think the main benefit is the same as with any law: if you have a law with no consequences for the people who break it, you don’t really have a law. If we don’t have immigration laws, we have an open border and with an open border, we can’t regulate the rate at which people enter the country. This rate can easily exceed the amount that the country reasonably accommodate, which negative impact on housing, healthcare, welfare, transportation, civic cohesion, and education systems.

Immigration law is standard around the world, with deportation being the standard response to people who violate that law. The more interesting question here is how you think a modern country will function and continue serving the needs of its citizens when it stops enforcing its immigration laws.

>you see from deporting immigrants?

Nice job sneakily changing "immigration enforcement" to "deporting immigrants".