I'd say that is super useful as someone who

1) cuts and pastes into plain text files often

2) often wishes to take data from charts and munge it, although sparklines are probably too informationally sparse to bother.

i was gonna ask how but then i tried it... very cool! i agree not very useful unless you want to do manual translation haha

only problem is the data is scaled to 0-100 so you won't know the real values