It’s all we have
If there is no helix endpoint for what you need/want to do that v5 is fine.
Kraken is deprecated. It will be removed and is not expected to get new features. New ClientID’s also cannot event make calls for Kraken v3.
v3 is even removed from the docs.
This is the same as how (basically) all versions of Windows (except 10) are (essentially) deprecated. (as a over simplification)
Still around but unlikely to get any major updates.
Definition:
(chiefly of a software feature) be usable but regarded as obsolete and best avoided, typically because it has been superseded.
“this feature is deprecated and will be removed in later versions”