Drawbacks of changing merit settings (ffdshow - LAVFilters)

[Dogway]

I come from the point that some renown users advice to NEVER EVER touch the merit settings, but without giving founded reasons (I'm even being recommended to uninstall ffdshow over changing merits link1, link2), and that is what I would like to know.

Originally Posted by CoRoNe

I'll say it again; there's absolutely no reason to mess with the merit settings or external filters in MPC-HC to play any audio or video file.
If I'm using it, it's only to block specific filters for testing purposes.

I already gave my reasons why ffdshow might be useful:

Originally Posted by Dogway

mix down audio, play strange video/audio codecs, post-process video with avs, or as you know preview avs files, etc. I thought it was a good fallback to have there because it's very powerful with its filter system

But it doesn't stop there! I also use ffdshow to encode FFV1 and to put an example just today nevcairiel gave another reason why relying solely on LAVFilters might not be enough.

Originally Posted by nevcairiel

LAV does not perform normalization. Don't confuse "Matrix normalization" with actual Normalization. Matrix normalization only normalizes the matrix coefficients, so that the sum of the coefficients for one channel never exceeds 1.0. If the audio is spiking over 1.0 before mixing, it will still do that after mixing.

So to sum it up, what's bad about ffdshow that people recommend me to uninstall it while I use other decoders, even over changing its merit settings?