The only beneficiaries are the non-essential employees, who get paid without having to come to work. It is a mild inconvenience to miss some paychecks, but they get the money in the end, and they end up having received large amounts of time off without having to use up leave.
The leaders of both parties (Trump and Schumer/Pelosi) benefit by showing their “base” they stood up for their principles, but they alienate the rest of the country which isn’t amused by the idea of giving a chunk of the tolerably well paid service a “no show” job at public expense.