It’s less worrying to me if Kamala doesn’t know how cloud data storage works than that Donald doesn’t know how tariffs work, which are the cornerstone of his economic policy.
The thing is, that video is from when she was the SF District Attorney. Google was looking to her for some legal expertise in the subject of data privacy. Even if she didn't know much ahead of time about cloud computing, how hard is to spend a few hours studying in preparation for such a talk so you can at least converse at a basic level with the audience? Can we trust that she will do her due diligence when talking to foreign leaders as POTUS about national security issues, or will she just go with whatever idea is floating around in her head?
I’m sure there’s a good answer to this question but in a binary choice election it is clear that she is superior to the alternative in this regard.
So even if she could use improvement and I am not conceding that she does (as you point out you are referring to something much earlier in her career and most people get better as they progress through their career) there is no doubt in my mind about the fact that Donald is way worse in this regard.