Hi yianni54,
It depends more on the specific design and type of latex in the two mattresses you wanted to compare (and “it depends” is the norm for almost any question about mattresses) and you can see some of the many factors that contribute to durability in post #2 here but in most cases … probably not.
You may prefer it for various reasons but you don’t “need” it no.
There are many types of latex and Berkeley Ergonomics doesn’t make their own. It would be the same or very similar to other types of latex that used the same production method (Dunlop or Talalay) in the same “blend” of natural to synthetic (and I believe they use all natural in both types). So if you compare their latex in an apples to apples comparison with other latex or the same type and blend it would be the same. The designs, layering, firmness levels, and components of their mattresses may be different though from other manufacturers that used the same type of latex in their mattresses.
In terms of materials … Pure Latex Bliss uses blended Talalay and Berkeley Ergonomics uses 100% natural Dunlop and 100% natural Talalay. This article along with post #6 here and post #6 here have much more detailed information about the different types of latex and how they compare to each other.
Of course I can’t speak to how one mattress may compare to another in terms of how suitable it may be for you in terms of PPP or it’s relative “value” unless I know the specifics of the mattress itself and the price (and if you list the specifics I’d certainly be happy to give you my thoughts) and of course it’s value to you may be different from its “commodity value” as well. Generically though … both of these make “latex” mattresses of different types and can certainly be better value (depending on the price they are selling for) than most mainstream manufacturers and they would both be worth including in your research and testing.
Hope this helps
Phoenix