Now, giggling aside:
When I showed off my finished concertina in at the SSI 2006, I remember Chris Timson saying something like:
"Hmm - maybe thumb straps could be of use on an Anglo...".
Maybe it was because the instrument felt to him like an Anglo, with weird buttons and thumbstraps.
(Correct me if I am off track, Chris).
I should add that the thumbstraps (which went off, permanently, in 2008) weren't "normal".
They were narrow, about 10 mm (approx. half the width of normal ones). The reason was that
since I wasn't carrying the instrument in the thumbstraps (I always sit down), I might for
various, non-explainable reasons bend my thumb(s) - and that would feel unpleasant. But that's
all history.
"Of course, your mileage may vary"
Yes - it may be useful for a certain playing style, and irrelevant for another.
/Henrik