If you're a self employed night club type DJ, then a DJ deck is the answer for you. My brother was for a while, he could claim half the money he spent on a recognizes DJ deck, back from the tax man in one financial year. The second half the second year. In effect he could buy a new DJ deck every two years, and claim the expense. But that just put up the price of DJ decks. That was one of many reasons why DJ decks were expensive in relation to a HIFI deck. At one time you could not use a moving coil cartridge with a direct drive deck, because of the magnetic field caused by the motor just under the cartridge. Belt drives had the motor as far away as possible from the cartridge, for this reason. A light weight plastic deck can give a horrible "tone" to the sound, compared to heavy weight slate/marble or other material, but a plastic deck is easier to carry from the boot of a van up stairs to a disco.
DJ decks, and HiFi decks do two different jobs. Some HIFI decks only played 33rpm records, because the sound quality from 7 inch singles was poor. Some DJ decks spend all of their working lives on 45rpm, and if the 33rpm speed didn't work the DJ wouldn't notice!
Don't use a Stanton 500 cartridge on you vinyl. They track at 3.5 grams and will trash your records, which should track at around 1.7 grams, too light if people are dancing on a dance floor.