having both is equivalent to having WFH (but without the cost savings to the business regarding office rentals).
People who want an office are likely doing so in the expectation that there'd be people there. What actually happens is that the office is semi-empty on most days, and you'd get a few ghosts here and there (unless there's mandated office days).
So in the end, hybrid (without mandated days) is basically the same as WFH.