His humbug was effective. He was a fraud, but the people didn't know it. The great and the small in the city of Samaria thought Simon was the real thing. They jumped on his bandwagon. This Samaritan, Simon, was a conscious agent for Satan, and knew he was using trickery to deceive the people.
Every generation produces swindlers who exploit gullible people eager to believe in voodooism.
It is strange that people would rather accept claptrap than truth. The kind of signs these people do cannot favorably compare with bona fide miracles. And the multitudes gave heed with one accord unto the things that were spoken by Philip, when they heard, and saw the signs which he did. Satan has real power and can pull wool over the eyes of sincere folks. We need to be alert to this and not allow ourselves to be hoodwinked by quacks.