God provided us a way to be "justified by faith apart from the deeds of the law" (3:28), partly since none of us can fulfill all of God's law. But then this raises a big question about the law.
In the last verse of Romans 3, Paul declares that faith does not void the law, but rather, we "establish the law" (3:31). According to Merriam-Webster and the context, "establish" means "to put on a firm basis" or "to make firm and stable", so basically, Paul is declaring that the law still has a place. So what role does the law have if it doesn't justify us?
Back in Romans 2, Paul uses the law to talk about how none of us can fulfill God's standards. Paul summarized that a few verses earlier in Romans 3:19-20 when discussing how the law shows that we are guilty of breaking it. In other words, from the law, we know that we have screwed up (and need a Savior). Additionally, Paul talks in Romans 3:21 on how God's righteousness is witnessed by the Law and the Prophets, which basically means that Jesus met righteous standards as written in the Law. Also, breaking morals screw other people's lives (which is part of the reason why laws exist in general).
So the law still has some importance today. It's just not used as a way for us to be justified (because we screwed up at least once).