The decimal is unnecessary and just crowds the widget when used on the panel. The Avg Temp for the GPU does not have a decimal, so it would also be nice to be consistent.
And maybe remove the “degree C/F” tag as well. I know what my localization settings are and the crowding also causes a vertical misalignment of the text as you can see in the screenshot, and might make the box a tad smaller, thus not crowding the panel as much.
I suspect this wont be seen by anybody who can make the change, so I will make a feature request on the KDE bug tracker site.