I'll preface this with saying NA has a boner for Kayo. Seriously. 77% of their games they play Kayo, having 100% pickrate on 3 maps as well. EA however has only 32%. Now this might just highlight that NA is weird and loves Kayo. But as this game becomes more and more utility based, (utility combo, site executes, fakes, etc) Kayo's pickrate should only become higher and higher. I'll break down each of Kayo's abilities and why, all together, it creates the most broken agent in the game (besides Chamber).
Zero Point:
On average, it takes ~12 seconds to rotate on each map. Obviously this changes on certain maps (Breeze). Kayo's suppress takes away 8 seconds off that clock. Kayo can outright shut site executes down, by suppressing certain members which wastes utility already used in setup. This gives them one of two options, wait for their util to come back, allowing precious rotation time, or they can brute force it using no util (the Bronze player creed).
Example: Two Omen smokes go down and Jett dashes into her smoke. Her Sova Recon Darts. Breach is about to stun + flash but gets suppressed. Now the other teammates are isolated from Jett with a smoke going up on the chokepoint, Jett easily gets picked off from the defenders as she has no one to back her up. This not only leaves this to a 4v5 but takes away most of the explosiveness from the opposing team.
Work Arounds:
Bait out Kayo Knife before hand.
Kayo fails the time because it is a very tight timing you have to get.
Flash
Kayo can execute two flashes. Left Click for a flash that will pop after 1.6 sec, Right Click for a pop flash after 1 sec. Overhand flash is a flash primarily used for teammates in set plays and executes and is very easy to perfect flash with. Underhand flash can be used for bursting out of choke points with a difficult flash to turn, and pop flashing out of smokes. A good Kayo places themselves at a small distance from the choke point so the flash pops directly there and does not give any time to dodge. A full blinded enemy is blinded for 2 seconds.
I don't think there is too much debate about this but this is the best flash in the game. It is so versatile in its uses which makes it so useful.
Molly
This is the worst part of Kayo's kit and its still pretty good. It's heaviness doesn't allow for too much lineups but it can be used to break KJ lockdowns without LOS thanks to the new buffs to his molly. It stalls for 4 more seconds and buys time for that 12 rotate time I was talking about earlier.
Ultimate
A 7 point Phoenix Ult that also suppresses everyone in a large radius? Sounds great. Ult lasts for 12 seconds, its a huge slow on defense side and great for executes on attack. Its an S tier ult for an S tier character.
I spent way too much time writing this so heres a tldr with a bit more
TLDR
Kayo is an agent which can do too much better than other agents. Whether that be his duelist-initiator hybrid replacing duelists on maps like Icebox. Or his flashes just being better. Kayo forces other agents into smaller niches because he can just do it all more reliably. Also cool robot man.