It's right in Sony's own documentation. Look it up.
Well if Sony says it it must be true........

I have worked on countless HLG videos in post.
I must not know what I am doing! :)

S-LOG = best for a post processing workflow.

HLG = for live broadcasting and monitoring in a 10-bit environment.

Simple as that.
Just because you can pound a nail with a screwdriver doesn't mean that the hammer wouldn't have been the better choice.

On my Z90 the HLG results are not great however for the A73 the results are excellent.

My work flow
Shoot HLG3 BT2020 PP10 on the Sony A73

FCPX
Rec 709 project
Import footage
Color Space Overide Rec.2020 per clip
Results look great, colours look natural.

I might have this incorrect however as I said, great results

I'm not familiar with the A73, does it have an S-LOG mode for comparison to the HLG mode that you say you like?

Yep, the A73 has Log profiles which I have found to more of a hassle, I normally use Cine 2 or Cine 4, however lately HLG3 has been my goto profile.

I wish there was more info on HLG and FCPX workflow as there's two two distinctive Color Space Override settings: Rec. 709 & Rec 2020
They both look great with Rec. 709 being less saturated

If you're happy with the results you are getting, then nothing more needs to be said. But that does not change the fact that HLG is not the recommended mode for post processing. Alister Chapman and I disagree about a lot of things, so when we both agree on something we are probably correct. Especially since what I posted above is also the official stance of Sony -- which is the developer of S-LOG and HLG. They ought to know what they are talking about.

What is HLG and what is it supposed to be used for? | XDCAM-USER.COM (http://www.xdcam-user.com/2017/07/what-is-hlg-and-what-is-it-supposed-to-be-used-for/)

Also, if you don't want to do any true color grading in Resolve, and instead choose to stay in an NLE such as FCPX, then you're not really getting the full bang out of S-LOG anyway, so a comparison to HLG is flawed. You think you like HLG but that does not mean S-LOG wouldn't be better if it was given a proper run. Have you used S-LOG3 and graded in Resolve?

I have graded SLog versions in Resolve and they work great.
SLog in 8-bit however is a disaster.