I'm against donating for items, but absolutely adore tip jar donations.
I feature a little coffee cup in the corner of the main menu of any game I develop, It'll send you to my Paypal where you can send 1 USD or more to buy me a coffee for developing some cool game.
It's the least someone can do, you know? Buying a drink for someone who made something you enjoy.
To me, donating for items is like doing a good deed and bragging about it to other people, especially with permanent vanity items.
It's just not cool, and pretty annoying.