Saddlebag / back supports

I own a Suzuki C50. I am getting old and on longer trips I find that it would be nice to have something to lean against. Has anyone tried one of the round passenger seat bag/back supports advertised in the bike magazines and on the internet ? There are several on the market -- like the Lazy Biker Cycle Bag, the Cruiser Bag or the Biker’s Friend Saddle Bag.

Are they simply a gimmick or do they work? Can anyone recommend one brand over another.

Thanks

Glendowery