I think a capsule might be handy for going over to peoples house with bubs rather than have to get the pram out as well, also maybe shopping as you cant push a trolley and a pram (but you could always jsut use a sling or a baby bjorn for baby instead....

Cant really thnk of any reasons. If you want to save money I would just get the reversable car seat. That is waht we are doing..I think!