The danger with a widely spread asymptomatic infection is that it might become symptomatic, or might be for some portion of the population. Or chickens.
Unless they are performing large scale sampling of the general population, the denominator (cases of confirmed influenza) is potentially much larger in practice.
Moreso because it seems likely that the confirmed cases are sampled from the sickest population seeking treatment.
And this article is further evidence of exactly this, since the "silent infections" here were previously uncounted.
Being surprised by asymptomatic cases suggests their IFR numbers are high on the page you linked, due to low occurrence and conflation with other colds (or asymptomatic cases).
Is there anything to suggest that the asymptomatic strain detected here is worse?
