I think that in most VTC platforms, the tendency is to favor quality/resolution for screen sharing and speed/FPS for camera sharing.
It sounds like your case is less common but the idea is that a video or camera feed can handle more compression (and subsequent drop in quality) as long as it isn't choppy or dropping out. Alternately, a slide or document may have small text which would quickly become unreadable if the compression is too high. To prevent that, you get high quality but only 5FPS or whatever so people can read your document or slide.
Slides and docs don't usually need high framerates so it would just be wasteful to try delivering a mostly static, high resolution, low compression 1920x1080 feed of a PowerPoint at 15 or 30 FPS.
There are ways around this (even on a consumer PC) such as using something like OBS to switch between sources like a webcam, a video clip, or a screen cap and feed them to a virtual webcam (which can be selected in your VTC software as the webcam input). Alternately, there are dedicated switchers and mixers but they're usually reserved for studios or in-facility installations.
But again...you may not like the results even so. The webcam feed often trades higher FPS for higher compression.
It sounds like your case is less common but the idea is that a video or camera feed can handle more compression (and subsequent drop in quality) as long as it isn't choppy or dropping out. Alternately, a slide or document may have small text which would quickly become unreadable if the compression is too high. To prevent that, you get high quality but only 5FPS or whatever so people can read your document or slide.
Slides and docs don't usually need high framerates so it would just be wasteful to try delivering a mostly static, high resolution, low compression 1920x1080 feed of a PowerPoint at 15 or 30 FPS.
There are ways around this (even on a consumer PC) such as using something like OBS to switch between sources like a webcam, a video clip, or a screen cap and feed them to a virtual webcam (which can be selected in your VTC software as the webcam input). Alternately, there are dedicated switchers and mixers but they're usually reserved for studios or in-facility installations.
But again...you may not like the results even so. The webcam feed often trades higher FPS for higher compression.