Having over 200+ products in a pastebin is a clusterfuck. It works for small sources, having 12-20 products which aren't ordered in the 100s quantity.
I'm very big on customer experiences (its my field actually) and its super annoying for a customer to have to multiply and add up his own orders while a website can have all that done for him in mere seconds, with everything in a searchbar's reach. One could argue he could just control+f and search and multiply himself, but the average customer today is lazy.
Plus, it looks pretty and I think gives me a tone of professionalism.
EDIT: I also forgot to add security. Being with all my servers in either Singapore/Russia/China with encryption, there is no breach of information for the customer. Some people just don't have a proton/tuta, and the website makes sure that isn't an issue.