i never understood why Hiawatha's usage hasnt picked up more than this.
According to w3techs Hiawatha is currently used by 150 of the top 10 million websites or 0.0015%.
A more detailed report can be found here https://w3techs.com/technologies/details/ws-hiawatha/all/all
The information can easily be checked with the following command, for example
curl -s -I www.localcities.com|grep Server
Server: Hiawatha v10.0