Travelling in time didn’t take very long at all, provided you were already in the right place. Travelling in space, even with Gallifreyan technology at your fingertips, took longer, hours at least, and sometimes days. Not even a TARDIS could jump dozens, or sometimes hundreds, of light years in a single bound, so some way of passing the time was needed to fill the interval between ‘here’ and ‘there’.
“Do you play chess?” the Doctor asked Rose.
“Chess? Uh, no, not really.”
“Pity. Love a good game of chess, me. Played against some of the greats. I could teach you!”