In many instances it is very convenient to think of antimatter as normal matter going back in time. This is what makes Feynman diagrams so easy to use and powerful.

Furthermore, CPT symmetry is a necessary condition for basically all scientific theories. This means that reversing time is literally identical to reversing 'charge' and 'parity' together - and in this context, reversing charge means swapping all matter for anti-matter and visa-versa. Reversing 'parity' roughly means swapping left and right across the whole universe.

... Anyway, CPT doesn't directly tell us that anti-matter particles are normal matter going back in time, but it does imply that that isn't a bad way of thinking about it.