Cadiz is a port on many many cruises. I think we have been there at least 8 to 10 times. Too many times that I have lost count. Will be there again in March!
Seville to Granada is way too far - you spend TOO MUCH time on the road both ways and only have very little time for what is worthwhile to see at Granada, namely Alhambra.
I were you I would heed Alex advice, visit Jerez and Cadiz instead.
