Maybe the main concern here was the legitimateness of a platform
...
It could easily be used in a crime but I guess you could still do it if there are platforms that you ready trust its security
There are no crypto platforms or exchanges anywhere I would trust with my KYC details. The small exchanges are obvious - their security is lax, and they often disappear or outright scam, taking your KYC data with them. But even the big exchanges cannot be trusted. Pretty much all of them use third parties to collect, process, and store, your KYC data, and you have no idea what security these third parties do or do not have, how securely your data is transferred, how securely it is stored, who can access it, and so forth. You also don't know how
they share you information.
For example, Coinbase transfer your data to a number of companies, such as Jumio and Sift, as laid out here:
https://www.coinbase.com/legal/privacy. Let's see how they handle your data:
Jumio also may subcontract the processing of your data to, or otherwise share your data with, its affiliates or third parties in the United States or countries other than your country of residence. The data protection laws in these countries may be different from, and less stringent than, those in your country of residence.
We may share your information with third party vendors, contractors, consultants, and other service providers who provide data processing services to us and with whom the sharing of such information is necessary to undertake that work.
Your personal information may be transferred to, and processed by Sift in, countries other than the country in which you are resident, including the United States, Ukraine and other countries around the world where Sift, its affiliates, service providers or partners operate facilities. These countries may have data protection laws that are different to the laws of your country and may not provide for the same level of protection as your jurisdiction.
As soon as you hand over your data to Coinbase, it is transferred to a third party, who transfers it to more third parties around the world in a bunch of countries with who knows what data protection laws. It could end up in the hands of literally anyone on the planet, and often does. Every major exchange is the same. How anyone is OK with this I will never understand.