Sync button. You set one master bpm and all tunes pitch into the right speed automatically.
You don't even need a laptop for it, just two cdjs linked via usb.
This.
It would seem that the sync function has rendered beatmatching an obsolete skill, like CDJs did to manual cueing. But I think those who still practise it do have something of an edge over those who don't. Time spent on the turntables means training on the mixer as well, and even using the jog wheels on CDJs trains the fingers in a different way faders, knobs and buttons do.
[rant] Automatization tools generally erode manual skills, from algorythms sorting emails into inbox and spam folder to car drivers taking directions from gps systems instead of reading street signs. Over time the skill is lost. Other examples: handwriting in the era of keyboards, proper typing in the era of swiping smartphones and tablets let alone voice/text interfaces like Alexa and Miri, or simply remembering something in the era of google, or selecting tunes from ear in the era of their bpms and keys being listed on Beatport and in mixing software. One has to make choices for oneself, which skills to practice (hard) & keep and which ones to automate & lose. If everybody just uses all available automating tools, it'll be the Borg in the long run, and only the element of random numbers / random tune "selection" will generate differences between sets and generally output from different people anymore. But it's obviously down to
users' personal preferences.[/rant]
A DJ I used to know once argued against the sync function that he wants to hear the DJ mixing, meaning he wants the analogue feel of hearing the small mistakes to appreciate it fully. But he also called the first BSE album "overproduced" when it dropped.
I personally prefer and give more respect to unsynced sets, but I didn't mind A.M.C. syncing throughout most of his 6 decks set. He made up for beatmatching with another skillset from outter space. Turntablists often even suck at beatmatching because they just don't take the time to use headphones, but who cares as long as they juggle and scratch it out proper with bafflingly well-selected tune combinations and play ten records in the time Andy C makes one double-drop.
I will take my hat now.