Why Networks like WSPRnet, PSKReporter and the Reverse Beacon Network are built from automated receivers (skimmers) that decode weak digital and CW transmissions and upload the callsign, frequency, time and signal report to a central database. Because the decoders work well below the noise floor and run unattended 24/7, they build a near real-time map of which paths are actually open. So the raw data these networks report is decoded signal reception reports, not geophysical measurements.
Watch out Solar flux (the 10.7 cm index) is measured by observatories such as Penticton and distributed in WWV/space weather bulletins, not gathered by ham reporting networks, though hams certainly use it alongside those reports.
WSPR, PSKReporter, RBN: robots listening for CW and digital signals, not instruments measuring the sun.