If you read the literature, they compare a symptomatic viral infection to having your hand or foot broken, or a pelvic fracture, or a mild to severe head trauma. I do not see any evidence of those things being equivalent.
For the person who suffers them, they are not equivalent. But that isn't what is being measured.
When measuring economic impact, they could very well be equivalent. A dollar lost when someone can't work due to a broken bone is economically equivalent to a dollar lost when someone bedridden with a virus.
Best case, your comment is an oversimplification of what the authors spent a dozen or so pages explaining. The limitations they describe perhaps encompass some of your concern. They also describe alternative calculations.
On the surface it doesn't seem like a bad comparison. Out of work for weeks, potentially protracted recovery including possible long term limitations. What's the problem?
When measuring economic impact, they could very well be equivalent. A dollar lost when someone can't work due to a broken bone is economically equivalent to a dollar lost when someone bedridden with a virus.