Carbontex gives a consistent/smooth drag even at high temperatue during a long fight. They also last longer than most washers.
Worthwhile for sharks and big game fish but for eds I wouldn't think you'd ever notice the advantages.
My Saltist 30 came with carbontex so maybe you've got them already. The standard washers in the old Saltist weren't that bad, many a big shark has been landed on them.