It is particularly important to mention that BTCPay Sever prevents address reuse, as many people has been reusing addresses in the past.
Here is why you SHOULD NOT reuse a Bitcoin address:
- Privacy: reusing the same address not only makes it incredibly easy to link it to your identity, it also compromises the privacy of your payers and every person that interacts with you.
- Security: by compromising your privacy, address reuse increases your attack surface, as people that want to steal from you or harm you would have A LOT of information about you and your payers.
- High fees: fees for a Bitcoin transaction are calculated according to the “size” of a transaction (which has nothing to do with the amount being sent). By reusing addresses, you are building huge transactions involving many inputs, that will cost you a lot in fees when you want to move them.
You can read more about address reuse on the Bitcoin Wiki