a single reason. But a solid one. It’s based in the USA and as such it follows US laws. That means it’s absolutely not protective of your consumer rights, privacy or even actual ownership to the domain name (Namecheap is known for various shenanigans such as weird renewal conditions that would be deemed illegal in several countries, and a tendancy to suspend domains without a legal reason and making it extra hard to transfer it after that).
I might be preaching for my own church here but if you do care about your domain, you should probably pick a registrar under EU legislation.