When it comes time for the toasts it looks way better in photos if the people who are toasting you can be on a wireless microphone for so many reasons:

1. A wireless microphone allows the person toasting you to be next to your table rather than across the room. This allows for the two of you and the person toasting you to be in the same photo while the toast is taking place. Everyones expression is caught at the same time in the same photos which tells the story of your day with a lot more emotion.
2. When the microphone is on a cord at the DJ table it produces a cluttered photo as DJ tables have a ton of equipment on them. The DJ will also be standing right next to the one toasting which means he may be in a photo or two as well. 
3. When the one toasting is across the room from you rather then next to your table it puts guest in an awkward position. They want to listen to the person toasting but they also want to see your response so they find themselves looking back and forth like a tennis match rather than a well laid out beautiful wedding day. 
4. It looks more elegant and planned out if the person toasting is next to your table. It also provides a more personal and cozy feel to the evening.