I'm not sure it does prevent Cut-offs on Bars. I think in some cases it actually increases the risks as the line is lower in the water. As for near snags, I view it as a complete NO NO!
(As I have probably stated on some of the other threads)
I have been debating its use at the moment and I had a Smash up with Leadcore on Thursday last week. The Leadcore was totally worn through on a Lily Root that had broken from the Main Patch and was embedded in the Lake Bed. Yet the Mono as it was not textured but smooth was wearing and rubbing over the Root. The Lead core was cutting and being worn.
I know that the Lead was able to break free on the Running set-up, as I reeled in about a metre of Leadcore that had been rubbed through and the Running Lead Ring was not attached to the line. So somewhere in the Lake the most the Carp is dragging around is a 15cm hooklink and a swivel with 5cms of Leadcore, from just above the splice
I use to get cut offs in the lillies caused by the roots I presume. This was on mono. I changed to braid for lower stretch and thinner diameter to cut through pads. Unfortunately, I was still suffering cut offs and lost fish. I changed to the leadcore setup and this prevented cut offs and I have not had the problem ever since.
I also used leadcore on my other water which has plenty of shelves and I have have not had a cut off yet. But I am struggling on that lake so am taking the leadcore off and lightening my entire setup. The lake is not silty so does not have the camouflage effect and I believe the leader has been sticking out like a sore thumb.
I am using ESP leadcore, perhaps your brand is of lower quality?
I have faith in leadcore getting the job done for me and that my rigs are safe. However, this knowledge of safety must be adopted by other anglers.