IO540, all our piston a/c use HSIs, RMIs + 2nd boxes as 'standard' OBS/CDI or rotatable ADF. But they're not used for training other than the required checks & training stuff.
I think ETOPS773 is referring to a rotatable ADF card - but trying to use it as a 'poor man's RMI' ie keep manually adjusting it to sync with the DI. NOT a good way of doing it.
Most of us seem to agree that learning to use the fixed cards method for that type of display is the better way. Many of us also seem to agree that it's easier to move from fixed to RMI use than the reverse.
My comments also referred to quite common setups out in the wild where RMI 'everything' is not particularly common eg my mob. Sorry if I wasn't as clear as I should have been.