There were 2 kinds of prophets which Moses warned the people about. One kind had power, but the wrong message. Another could have an innocuous message, but had no power. A true prophet of God had to pass both tests. He had to have a message consistent with the messages of the former prophets who had already been proven to be legitimate ... and he had to have real power to validate his message. This "litmus test" was very important when Jesus came. Those folk who claimed to have so much reverence for the words of Moses should have been obligated by their own standards to accept the validity of Jesus' claims. He stayed consistent with the former prophecies like nobody had ever done before; and, His immeasurable power proved that God was with Him.
Now, when the antichrist comes, he will have great power, but his message will contradict all former revelations. According to this chapter, a false prophet, friend, family member, group or culture that leads people away from God is worthy of death. Even so, the antichrist will be worthy of nothing except death... and that will indeed be his end.
In the days of Moses, everybody associated with idolatry... as well as all of their belongings... were supposed to be destroyed without pity. Thankfully God hasn't given me (and, I can safely say, won't be giving me) the responsibility of executing that kind of justice, but that doesn't mean that I don't recognize the reality of His impending wrath against all idolatry. Whether now or later, all idolatry will garner more than enough negative justice from our God, whose name is Jealous (Exodus 34:14). No wonder in the NT Paul was still willing to declare with simple urgency, "Flee idolatry" (I Corinthians 10:14).