Very good for physio work and can be handy as a "gym in a bag" for staying away – make sure you use high resistance though and Theraband make the best.
Pretty much fixed a very dodgy shoulder with one of these.
Use a bit of creativity and you can use them for biceps curl, shoulder raises, seated rows and many more exercises using a chair and/or a stury door handle to hang it from.
You can actually wrap one around your shoulders and hook them between your thumbs for a then assume press up posisiton for VERY variation. It's hard to get it right thought – best elevate your legs for a more intense press up (if needed).