I hope I put the post in the right place, I'm new in this

I would like to comment that I read the guide "icy-veins" and I was surprised that say the 4 pieces of tier 21 should be put only if they were from Antorus-Mythical.
I quote verbatim
"
The Antorus Tier 21 set bonuses are generally underwhelming, especially the 4pc bonus, but you will generally want at least 2 pieces of it. You will most likely not be swapping to Tier 21 4pc until you have a full set of Mythic Antorus Tier gear.
"
Most pieces of my equipment are from Antorus- Normal.
I would like to know your opinion about this, since I really do not know if I should have put the 4 pieces or change them.
Thanks a lot!