Well you are mixing 2 things here
WEBi (which has been replaced by ICN) is using the JAVA Api from ODWEK.
The Java API from ODWEK are not using ARSWWW.INI at all.
ARSWWW.INI ist ONLY used by the ARSWWW.CGI component of ODWEK. Therefore any changes in the arswww.ini will not be seen by WEBi/ICN/...
Probably with the newest version of CMOD coming at the end of this year (if everything is going as planned), then the servlet/arswww.cgi/arswww.ini will be removed forever. since they are deprecated since a few years now.
If you want to have the folder descriptions, then you can migrate to ICN, because ICN per default displays the folder name and show also the folder description.
There are tons of new things with ICN, but this one is one of them.
Hope that helps.