I'm a bit behind the time on this and referring to IO540's earlier post, I do enjoy reading his various diatribes
The usefulness and functionality of a device is not inversely proportional to its longevity, often the opposite! Nobody in their right mind would use a whizz-wheel in the cockpit, it is only a planning tool. Rules of thumb technique are necessary/essential knowlegde and I've never met an instructor who disagrees with this. Rules of thumb augment any navigation method be it VFR, IFR, GPS, RNAV, DR, etc.
My observation is that learning to use a whizz-wheel is really part of the process of ingraining the notion that you need to be vigilent with regards to the various metrics and conversions required in the flight planning process. I would argue that the use of one universally capable metrics tool in the training process helps structure and standardise the corresponding processes, rather than having to use this piece of software for this and that calculator for that, etc.
