It is required for Laserfiche Scanning. If you do not install that module you should be fine and the installer will not prompt it.

I was curious on your source of a patched .NET 3.5 install being insecure so I did some googling and did not find much. It is just annoying that often times we have to get this installed on client machines as it does take awhile.

Thanks for your reply John. Here's a list of security concerns in .NET frameworks prior to 4.5 (Note some may have been subsequently patched) but it is best not to use versions prior to 4.5.

https://www.cvedetails.com/vulnerability-list/vendor_id-26/product_id-2002/version_id-82466/Microsoft-.net-Framework-3.5.html

I got that link from googling .NET 3.5 Security concerns

Another topic of concern with .NET versions prior to 4.5 is with TLS. TLS1.2 is being required by many companies due to security concerns. TLS 1.2 is not in the enumeration for SslProtocols in .NET 3.5, it was added to the enum in .NET 4.5.  See: https://stackoverflow.com/questions/43240611/net-framework-3-5-and-tls-1-2  Or a google search on .net 3.5 and tls 1.2