It's risky since you trust a third party to secure your private data without any control whatsoever. If you read some news about database leaks, you'll be surprised at how many of those happened within a year. Exchanges or any third-party platform is a high-profile target for hackers to attack, one of their targets is their customers' data so they can sell it on a marketplace. We can't even guarantee if the exchange abuses our data or not. I'd avoid KYC if possible, or try to minimize the number of platforms that I give my data to. CMIIW.