I’m surprised at the question; algebra is merely a part of mathematics, so the question queries the basis of teaching maths.

Much depends on how you want to live your life. There was the earlier example of “how many bottles of pop for $10?” then there is “How much does my electricity cost per unit?”, “How much of my tax goes on defence/welfare/public servants/roads, etc?” “What is the effect of reducing any of these by certain percentages?”

With the latter questions, you are beginning to understand the uses of math(s) – and, with maths, comes statistics. Government is based upon statistics; no one collects more stats than government. Stats can be tortured and manipulated to prove anything – particularly a political point. Without knowing the real answer, how do you know for whom to vote? If you don’t know, you are at the mercy of unscrupulous politicians who tell half-truths.

Learn and learn to use math(s).