Are you talking about those flat ribbon cables? Those are designed like that for a reason: the shape keeps the distance between the wires constant, which reduces variability in the capacitance of the cables. Capacitance is one of the variables that's important in estats (high capacitance makes it difficult for the amp to drive the high frequencies) and keeping capacitance low in the cables is more important in estats than on regular headphones.

Not all estats use those flat cables. IIRC, the DCA Voce uses a cylindrical cable that's more similar to regular headphone cables. The Hifiman estats use a thinner nylon mesh cable, though it's still roughly flat. The Warwick ones also use a round cable. I think the Audeze CRBN also doesn't use a flat ribbon cable either. It's mainly Stax that does it, but for good reason IMO. Personally, I don't like the handling of those ribbons either, but there's a valid reason for it.

And regarding voltages, most modern estats have standardized on the Stax Pro bias voltage (580V DC). Only a few estats use other voltages (Warwick and Sennheiser), and Koss uses a weird connector, but their estat is decades-old.