I learn songs that alan day has presented... and i am starting to automatically improvise with it, for my own enjoyment... not well at all, i admit.
There we may have the answer! If you'd practised your scales a bit more, you might be improvising quite well by now ...
One point of learning scales is the following:
In the music that most of us play, there are 12 notes in an octave, but the vast majority of our tunes need only 7 of these notes. So there are 5 "wrong" notes lying around, and we have to avoid them. This is particularly important for those of us who play by ear or like to improvise. (The sight readers can read the "right" notes from the sheet music.) So we learn the scale of C major, G major, D major, A minor etc., etc. so that when we're in that key, our fingers will know what notes to use and which to avoid.
In the case of a 20-button Anglo, practising scales is not so important, because, if you play along the row, there are no "wrong" notes to play! But try playing a tune that's in your head on the fiddle or mandolin without having the scales in your fingers! Other concertina systems, like the Duets and the EC, also have their full complement of "wrong" notes, and practising scales gives you the knowledge of what notes are appropriate for the key you're playing in.
@MJGray: if scales "bore the pants off you", perhaps you're not playing them very well! Plodding along "doh, re, mi, fa, so, la, ti, doh" and back again is not "practising scales". If you do play one note after the other, at least phrase them, or introduce some rhythmic variety. But most scale exercises go "Doh, re, mi, re, mi, fa, mi, fa, so ..." or "Doh, re, mi, doh, re, mi, fa, re ..." etc. Play them in differnt dance rhythms, play them legato, play them fast and slow, phrase them nicely - in short, do with them what you would do with a tune that's in your head.