Stormcast Stormhosts

[Requete]

On page 117 of the new SCE battletome under "Stormhosts", the rule says that you can give your force a Stormhost keyword. It says that you can pick a Stormhost from the list, or use your own and associate it with one of the listed ones. In either case, you benefit from the "extra" abilities listed under those Stormhosts.

People on this forum appear to assume that you must either use a Stormhost and all the listed abilities, artefacts, etc., or go with a generic group and use the abilities at the beginning of the section (with classics like Staunch Defender and Mirror Shield, etc.). Where does it say that this is an "either/or" choice? I don't see that text. It appears to me that you get access to the generic stuff and the Stormhost-specific abilities, since those are described as "extra".

That is how it reads to me, but I'm posting it as a question because no one else seems to read it like that.

[Gecktron]

When using one of the pre-made Stormhosts you have to give your Warlord the Stormhost specific warlord trait (which prevents you from taking one from the list) and your first artifact has to be the Stormhost specific one. But you can take one from the list if you can take a second artifact (for example by taking a battalion). 

[EMMachine]

I don't have my Battletome yet, but it should be actually the same thing as Temples of Khaine (Daughters of Khaine) or Enclaves (Idoneth Deepkin).

It's additional, but like @Gecktronsays, often parts like the first taken Artefact or Spells get overridden by the Stormhost or the equivalent of other armies.