This is a common and incredibly stupid argument. Note that it immediately implies that oral communication in English and Japanese is impossible.
Early video games didn't have the memory available to render text in kanji and used kana exclusively. This caused zero problems.
There's a lot more context in speech and video games and long-form writing than in random writing and signs. It's virtually impossible to convey a meaning to a product or company name without using kanji.
For example, let's take a company named "Bandai". Now look up "ban" (https://jisho.org/search/ban) and look up "dai" (https://jisho.org/search/dai) and "da" (https://jisho.org/search/da) and "i" (https://jisho.org/search/i), each of which has 3-5 meanings, and tell me which combination of possible words is the company's name derived from? There's literally no way to tell.
What combination of words was "Xerox" derived from? Does that affect the meaning of "Xerox"?
How about "Samuel"?
"Rachel"?
"Ted"?
Only if people communicate without context. A large amount of ambiguity can be removed by understanding the context of the conversation.