Hancock must have been practiced at calligraphy. His signature really is beautiful.
Everyone who could read and write back then had 'beautiful' writing. Especially the 'more educated' class. Plus the Quill Pens they used added that 'calligraphy' touch.
But alas, today kids don't spend much time in school on 'writing script'. But not that it would help, they can't spell either.
Most educated people of the time had beautiful handwriting. It was the MARK of an educated person, and some schools today still stress it, though too few, sadly.
If you look closely, you'll see all the signatories had good penmanship.