Yeah it make the lens look more even when lit up and you can convert them to one lamp per cross section fairly easily. The one thing I like about the wraps with the ballast channel is that the lamps are more widely spaced.
(...) I'd actually say you could possibly fit a channel cover between the lamps; they're nicely spaced apart. The reflector/wiring cover was secured in these by two spring-loaded flat clamps that you'd rotate 90 degrees (the predecessor to the quarter-turn clips) so a third center lamp wouldn't fit. Looks like this wrap was only designed for two lamps. If there was a single or three lamp version it must've had a slightly different design.