I feel like they should. Just so that if you were on your phone on safari it wouldn't have to be ON SAFARI. I think that an app and on the safari would be best.
Unfortunately, no matter how many times the idea has been proposed, it has been declined, as Nicky Midnight has shown you. The website functions well on mobile as it is, and if you wish to use more than one website while on browsers such as Safari, you can just open a new tab.