Hi I understand your project. Like your other project the swap "protocol" Lumenswap, its merits are a bit exaggerated. Calling it a "payment gateway" is really a stretch. Coinqvest is a payment gateway. Your project is an invoicing utility at best. The only thing it really does is a calculate how much XLM to show for a given local currency.
I just have a hard time seeing why someone would use it. You save the buyer 1-2 steps of Googling "5 USD to XLM". But at the expense of adding 2+ steps to the seller to create a link and keep track of all his payment IDs so he can check them. And also add 2 steps to the buyer to have to use your app and copy the address and memo.
All it takes is for Lobstr to add a currency to XLM conversion in the Send page and this project becomes completely obsolete.