First check the regs for the flow you're going to use them on.
Yes, they do work,
but that being said they will not help you catch them if you don't fish them properly and this goes for any bait/lure you choose.
Sometimes worms will be the lure de jour and likewise roe, spoons, bugs......
You can have the best bait of the hour and still not catch anything if it's not presented properly, in the zone.
It is a good thing to have in your arsenal but don't think it's the bomb.
Some flows have better success with them then others but it depends on so many variables.
That's why I carry some rubber ones with me instead of digging up the garden every time I go out.
Sometimes it's just the change that makes the difference not live vs. rubber
but then again sometimes it just has to be live and you don't find out till the next day that you were so close......
Good luck but don't get stuck with one enticer just because a friend said...
Worms are as old as dirt.