That's actually not the case. The original spaceport scene in 'A New Hope' was meant to be between Han Solo and one of Jabba's lackeys. Who said similar things but on Jabba's behalf. This was designed to create mystery around the character of Jabba, and leave the viewers guessing as to what he would be like until his debut in 'Return of the Jedi', where he turned out to be nothing like they had suspected - a overgrown slug. However then Lucas released the new editions the scene was changed so Jabba would appear in the spaceport. This is one of the few changes that Lucas made to the films that actually irked me (I don't really care who shot first). Because it loses all that build up, and it doesn't fit in with lore either. A Hutt of Jabba's status would never have come to see Han Solo personally.
I do like Hutt's being big slugs though. It just embodies the concept of a 'greasy', greedy, gluttonous and unpleasant crime lord.
Meh, maybe it's just me but I think the inclusion of that scene was more an excuse for a Boba appearance than anything else.