Why cannot the app be copied to the SD card?
Technically, there's no problem copying parts of the app to the SD card - it can be achieved by modifying a single file in the app's manifest. The reason why I don't want to support this feature is that SD cards tend to be quite unreliable compared to the phone's internal storage and files copied to SD cards can get easily damaged which leads to app crashes and bad user experience.
In addition, the amount of data that could be copied to the SD card is very small for Network Analyzer - it's about 1.5MB so the space savings would be marginal. I try to keep the app as small as possible - it's less than 6MB to download from the Play Store and less than 10MB when installed so it shouldn't occupy a significant portion of the phone's storage.