This is intended to be a question addressed to all those who play on digital instruments, therefore with pre-packaged sounds rather than real ones..................given that I also have a Roland for nighttime playing and an upright for actual study.
So the question is this: don't you fear that the sound obtained after so much study on a piece (on the digital) might not actually correspond to the real sound produced by a true piano?
When I am teaching, people who use only digital instruments, once tested on the teacher's grand piano, appear lost to me, lacking color, dynamics, and sensitivity.
I mean, it is nice to hear the sound of a Steinway, but are you sure that you are then capable of making a real Steinway sound that way, with that cantabile, etc.....
A single consideration to make the discussion more complete.............
pressing a key on a mid-range digital (setting aside those from 2000 upwards just so we understand, which almost no student owns or can afford), the sound produced by a first-year beginner will be identical to that of millions of other students using that same piano model, whether it be pp/p/mp/f/ff; unfortunately, this is what distorts everything, just as the same sound will be produced by a graduate, etc.....
It does not correspond to reality because it is infinitely repeatable.
On an acoustic piano, the timbre variations are manifold; whether you play a Steinway or a Siheko, the sound you obtain is personal and yours......
The pianist must know how to adapt to every piano, but an acoustic one; everything else is "fiction" and play.
I am not against digitals, which by the way I use at night for obvious reasons; I am just saying that I would not recommend them to beginners, especially in the first 3/4 years, the period during which the sound is formed and sought out.