Yes.
> Were there other forms of "phonetic writing" at play?
At the time that quote was talking about? No, since at that time, proto-cuneiform (as they call it) would have been the only writing system in existence. Go forward a bit, though, and several forms of “phonetic writing” begin to appear frequently: rebuses (as in the quote), syllabic characters (e.g. [baʼugeš] was written BA-UG₇-GE, Edzard 2003), and characters for individual consonants (unattested in Sumerian, but Egyptian used them extensively).
> If yes, then does that mean that there actually were case of symbols appearing directly as written translation of phonetic "concepts"?
Exactly. (Even my earlier quote has examples of that.)
At this point it’s just silly to brand your security product as Swiss made in hopes of looking more legit. In a sense I see it negative, just like some companies brand their products with buzzwords such as AI and blockchain for no good reason other then to look cool. Makes me suspicious.
And for the international market, probably "swiss" is mostly to be understood as "not american/russian/chinese"