Pretty much every place you can buy sponsorship in the Monero world does so over email, DM or Telegram. This is really shady and unprofessional in my opinion. It leads to impersonation attempts and moreover, the price for what you are supposed to pay isn't based on a shared truth in what the price is.
I understand that 3rd party processors take fees but there are very basic solutions that can still create an invoice on a site at the very least. Setting up BTCPay Server or similar does take time, I do understand. But it doesn't reflect well to accept payments in such informal ways.
I would really like to see the use of invoicing be more common for payments. Someone can easily spam people who want to sponsor MoneroKon, Monerica or Monerotopia with a fake payment address over email of DM. That can't happen so easily when the payment invoice is hosted on your own domain.
It's understandable that it seems easy to just send payments over DM but it opens up someone to risks that can cause brand harm.