I, also have been using a scanned signature for many years. When I worked for a credit card company, about 12 years ago, I had to submit 5 or 6 reports every day with my signature on each one. They had to be emailed and hand delivered, on paper every day right before going home for the day. The emailed version did not have to have a signature, but the paper one did. What a pain! I used my flatbed scanner (how long ago was that?), at home to scan my signature, saved it as a jpeg, copied and pasted it to the necessary documents, and away they went to the printer. No one ever questioned the fact that my signature was not not signed in ink.
I still have that jpeg and use it occasionally to 'sign' documents, when necessary.
BTW, thanks for the tip about the signature thing in Adobe Acrobat. I wasn't aware of that feature. I'll have to check it out.