Generally, there are three types of chandelier lighting and these are: task, mood and ambient, and each of the lights in your function room will perform one of these three functions.
As a rule, you would use chandeliers to provide mood lighting to your function and you might use this kind of lighting over a dining table. But, if you wished, you may also use chandeliers as an ambient light such as what you might find in a hotel lobby, or the grand entrance or hallway of a large house. The ambient light would be supplied by down-directed shades which work to diffuse and spread the higher-wattage light across a wider area.
Any chandelier that supplies mood lighting should be equipped with a dimmer so it can perhaps be turned up while guests are eating and turned down after the meal when the focus moves to the entertainment and the dance floor.
Of course task chandeliers can be used and placed directly over the task area and these can include lamp shades which direct the light into the task area. This would be useful in an exhibition environment when guests are there to view luxury products such as cars, yachts and antiques and it is vital they they be able to see them clearly in order to make a purchasing decision.
As a general rule, while the chandeliers can be the primary light provider, they should not be the only source of light in your function room; it should be augmented with accent lights at well placed locations in the room.