You will not be saving any CPU or memory in any way.
I had downstream rules in mind and not having to trigger some rules for a tiny tiny change of a value would be a gain. I would be happy to spend a bit of CPU/Memory to reduce the downstream load. For instance, I really don’t care about nano ampere/volt changes… none of the sensors are that precise. But to be fair, OH cannot know what is relevant and what is not. So the rounding you suggest sounds like a good option.
Ok, it sounds like I have some options. I don’t think debounce can really help but the 2 other options sounds relevant.
I am btw also suspecting that the high frequency of the changes may be the cause (or another issue worst) for this issue.
No matter how full logs are they are never “useless”.
Sure, using a console, I could grep away the noise. I guess that people (incl. me) mean that the web base tail page becomes useless since the ratio of relevant values vs the spamm is very low.
Even better would be to setup some Loki or something of the sort, it is on the list 
Thanks Rich !