Clarified to be only a portion of expenses, not half.
Looking at the original Japanese, someone may have jumped the gun with a bad translation, which is how this got picked up.
Page 5 of the summary of the supplementary budget states that the maximum amount that would get subsidized is
20,000 yen per person per stay, in the form of coupons that would offer up to
half off of travel-related goods. My guess is that would be mainly for omiyage.