Mobile phones and tablets have had a significant impact on my job and has had a significant improvement to how my TOC operates. My personal belief is that it was a new skill to be learned and new technology to learn to use. I can absolutely see why someone would want to be trained and remunerated accordingly. From an outside looking in point of view it doesn't seem that way as 'everyone has a mobile' but importantly, those that are doing the role see things very differently.
I completely agree with "trained", but not with "remunerated" unless the change to the job role in terms of added responsiblity and/or effort is significant. Another example would be non-revenue guard to revenue guard.
If e-mail needs to be used when it wasn't before, absolutely training (and provision of appropriate equipment if not wishing to use one's own) but not additional pay, because it's just a modernisation of information dissemination. Technology, and job roles, don't stand still, and nor should they.
Another example of where increased pay wouldn't be justified is when Aldi went from keying prices to scanning barcodes. Same job, different method. But training in the use of the new tills should certainly be provided at employer's cost and in employer's time.
Where job titles are descriptive, then they are a good start as for when more money would be justified. An Aldi "checkout operator" would still be operating a checkout even if that checkout changed completely. But if they were to be changed to be a "self-service checkout supervisor", while that's a similar level of job it's a material change from sitting at one till selling stuff to people to dealing with multiple tills etc.
A guard is still a guard even if they have to read their daily notices on an iPad instead of a notice board and scan e-tickets instead of clipping paper tickets. And they're still a guard if the rolling stock changes, too - I'd expect training to sign the new stock, but not additional money as it's just a change of equipment.