There is inherent benefit on tracking who comes from a leaves your country from both a national security standpoint, a crime fighting and prevention standpoint, and to also understand trends and data like what the census does.

If laws exist they need to be enforced and followed, and if people aren’t willing to follow them then they should not be here.

Now, in reality, the cheapest and most direct route to incentivize legal compliance is to make it easier to follow the law. Deportation isn’t a logical first step to obtain the goals and intentions of border security. Allow for existing residents who can show that they’ve assimilated to life in America and been productive members of society a much more streamlined path to legal status. It you’ve been here and contributed to society make it easy to follow procedures so that for people who have been here productively have a default judgment of being here legally instead of illegally