Never had one for DS1 and i'd fiddle around with a blanket and it was a bit of a pain.

I got one when i was pregnant with DS2 and i have used it since he was about 6 months or so and i use it every time i put him in a trolly.

Not sure about where you are but here at our local shopping centres most require a coin to release them from the 'pack' so that disgusting chain is constantly hanging down and always such a temptaion to be put in the mouth. With the cover i can hide it out the way and it's not an issue.

Personally i'd say it's worth it