There is a critical difference - everyone knows that 'dollar' is the standard unit, in the main, all software and formal presentation is in unit dollars, both because that is the standard unit, and because that is the normal scale for everyday transactions.   

The logical comparison is much closer to 'cents' '¢' that to 'grand' (and while the US has quarters, dimes, and nickels, that is far from the norm)

The move to 'bits' is more fundamental, in that it will likely be the predominant usage down the line, and furthermore, will be the basic denomination coded into many systems, with satoshi 'cents'.  For display purposes we, along with many other companies, will be showing values in 'bits'; and it is much better for the ecosystem to support quick understanding and ease of use of 'bits' in the everyday world.