You are likely to only refer more than current era. If you’re writing govmet grant application, renewing licence or certificate, chances are you mention events hapenned in previous era. You look up table for when the previous era started and ended, which era said year falls into, then convert for each year, each era. Extra minutes wasted every time instead of simply writing in Gregorian year.
It’s just how they word layoff and severance package. In Japan voluntary resignation can be also entitled for severance package depending roles/duration of employment, and this gives larger package than regular voluntary resignation is entitled to, to make them resign “voluntary”.