okay - they are primarily a continental lead for use with the lighter conti rods. However I have a few casting lads that use them for practice (as they are easy to see on the casting field) these guys know how to cast and are good at what they do - up to now I haven't had any snap or any complaints...................... generally you wouldn't be pendulum casting a continental rod - so they were not designed for a pendulum cast... they are called continental leads for that reason
The choice is yours I can only tell you what my experience has been .......... to my knowledge (up to now) they haven't failed in a cast with the tournament casters that I have dealt with.
There is no polite way of saying in the wrong hands with a snatchy cast I wouldn't be happy - so I wouldn't be so brave as to say they are fine for power casting ... it depends on the person on the end of the rod to be honest..... if I am not happy with any equipment I use (thats not to say its bad) ) ... I wouldn't use that equipment..................its just the way I am. On the other point - they were not designed to be buried in mud or shingle - the continentals fish clean beaches - no point in having a rubber coated coloured or lumi lead if you are just going to bury it. Generally uncoated NON continental leads have loops not swivels
I hope all of this makes sense?