The point of the party is to celebrate the engagement, just like a birthday party is to celebrate someone's birth ..and how do you celebrate? With gifts!

As long as the engagement party is at least a year (or close to it) before the wedding, then it's completely fine and tasteful because if you think about it they could use someone of the gifts from the engagement party towards the wedding they are planning for the next year. When a couple tries to have a party and a wedding within 6 months of each other, that's just tacky.