I almost always use some kind of funny prop when doing a presentation that is supposed to have a high percentage of humor.
Some props are just funny looking themselves, . . . like putting an Elvis wig on yourself or an audience member.
Other props need an explanation to be funny. I use a little odd looking piece of plastic that holds socks together so they don't get lost in the washing machine. It's not obvious what the prop is until I tell the audience what it does and why I so desperately need a sock organizer.
I like props because they offer a different way of keeping the audience member's interest. The concept of "keeping interest" is the cornerstone of my entire "Wake 'em Up!" speaking system.
Funny props also take some of the pressure off of you to be glib with your humor. You may want to add some humor to your presentations and you may realize the value of doing so, but you may not feel confident enough to pull it off. Props can save the day because funny looking ones can carry the load for you because they inherently get laughs even if your timing is not perfect.
This doesn't mean that props don't take skill and practice. You have to know when they should be seen and when they should behidden. And if they are hidden, you need to know just when the right time is to reveal them. If you are on camera, you need to know how to hold them so they are seen by the camera.