Here are some Business Cases that are relevant to ProSale:

TV 2 in Denmark The use of ProSale by TV 2 in Denmark.
Kungsbacka article GP
Kungsbacka article CS
Court Ruling
In the autumn of 2013 meeting protocol was signed electronically with ProSale Signing in a working committee within Kungsbacka municipality. An individual reported this procedure to an Administrative Court as the protocol did not have a visible ink signature. The Administrative Court dismissed the application in the spring of 2014 and individual then appealed the judgment to the Administrative Court of Appeal, which also dismissed the appeal. The court rulings are available in Swedish only.
US Patent 8,549,301 B2
United States Patent No. 8,549,301 B2: Method and computer system for ensuring authenticity of an electronic transaction
One reason not to use ProSale
This can be a possible reason why not using ProSale.