I appreciate any favor that the bridal couple gives as a thank you to their guests-
don't understand the comments about leaving them on the table or tossing them
To me, it's like leaving gifts you get at your birthday party behind because you don't like them.

To leave them behind is insulting. Take it and throw it out, or better yet, donate it. Someone creative can take whatever it is, even personalized, and make it useful for themselves.
Another one I've seen recently that I thought was pretty cool was a little tree sapling. (I think someone else also posted this idea further up the chain). Guests got to take home a little tree and plant it in their yard. I thought it was a great idea because it is lasting, useful, and very environmentally friendly.
I love this! We once got some sort of herb in a little planter with a note about the meaning of the herb as it related to...love?

LOL It was over 25 years ago.
That one I would leave on the table- spent thousands getting rid of all the trees in my yard so I could have full sun, not planting new ones!!
Again, I don't understand leaving this or any other gift on the table.

In this particular case, the only scenario where I could really see leaving it behind is if it would not be feasible to take it on a plane, in which case I'd thank the bride, let her know I was unable to take it but that (hopefully) someone else would. Otherwise, if you don't want to plant a tree, give it to a school or some other organization.
Lots of weddings but 2 favors stand out. One was a box of Petits Fours from Divine Delights. That was over 15 years ago and I order them now all the time. The other was a donation in our name to a children hospital. That was my favorite.
Always love a good food item

but I really love the donation idea. Not common back 30 years ago when I got married, but I'd definitely consider it now.