Practical concerns about illegal immigration?

What are the detriments you see concerning illegal immigration that you believe makes it a major issue?

Certainly a person who commits murder – citizen, legal immigrant, or here illegally – should be arrested and charged. And as part of the sentencing their status can reasonably be taken into account to result in deportation if convicted.

But how does a mere border crossing, or an expired visa, (or whatever circumstances) deserve massive crackdown on its own demerits? Speeding, driving with expired registration, and jaywalking are, for example, illegal – yet we treat those with less response such as tickets or civic fines

Further (follow-up question), are there ways you think the law could address those ills differently? Ie, if the issue is tax evasion then why not fund more IRS enforcement to ensure they also pay taxes via Tax ID even if they don’t have a SSN? Would not addressing the social ills directly and without strict borders be sufficient, or is there something specific about civic boundaries you view as important in and of itself?