It's not really a ridiculous idea, it's just that from a public health point of view it's not likely to be as necessary (in terms of truly catastrophic, rather than just awful, effects on the health service and society) for flu as it has been for covid, because there's more immunity to flu out there than there has been for covid. Also, people rarely know that they've got influenza, specifically.
From an individual point of view, if say your dh has flu or even a bad cold it actually would be a really good idea to avoid visiting vulnerable people for a few days (the incubation period for flu is much shorter than for covid, so four days would be enough I think).
For any infectious disease, it's worth having an idea of (1) how likely you might be to be incubating it if you're a contact, (2) how likely you might be to be able to pass it on before you're obviously ill yourself, and (3) how long you might be infectious after you've recovered.
Depending on the particular disease, you might then change your behaviour by, say, not visiting your granny in her care home within a few days of your husband going down with flu. Or you might (a revolutionary idea, this!) keep your children away from school for 48 hours after diarrhoea and vomiting. Or you might change to meeting a friend for a walk outdoors rather that going into their house, when you've got a stinking cold - that last one I can imagine people doing in the future when they wouldn't have in the past, thanks to covid.
None of that is ridiculous, it's just not something most people have been in the habit of giving a second's thought to - mostly we act as though diseases strike completely randomly, and don't think all that much about whether we have a personal role to play in breaking or extending chains of transmission. Maybe people will think about that a bit more from now on though.