Grandma doesn't care if her tablet can't saturate a WiFi 6 link. Grandma doesn't care if her bank's web page takes an extra 75µs to traverse the user-land network stack. But she will care a whole lot if her savings are emptied while managing her bank account through her tablet. Even worse if her only fault was having her tablet powered on when the smart toaster of a neighbor compromised it because of a remotely exploitable vulnerability in her tablet's WiFi stack.
Or are you suggesting that grandma should've known better than to let her tablet outside of a Faraday cage?
> Pretending that it's trivial amounts of performance drop without evidence is the wrong approach.
Amdahl's law begs to differ. If it takes 5s for the web site to arrive from the bank's server, spending 5µs or 500µs in the network stack is completely irrelevant to grandma. Upgrading her cable internet to fiber to cut these 5s down to 500ms will have much more positive impact to her user experience than optimizing the crap out of her tablet's network stack from 5µs down to 1µs.