Garden Tubs Question ( possyOT)

Hi-All you gardeners out there and others with gardens . I had a discussion with a friend recently about the use of those fancy glazed plant pots that you see in garden centres . I had always thought that they were used for holding plants which were already in plastic pots to make them look nicer but she thought that they were used as actual plant pots with the plants being potted directly in to the glazed pots . Ive never looked very closely at the glazed ones to see if they had drainage holes but I suppose either way they would need them to allow the water to escape. Stuart s