It will completely disable the airtime fairness scheduler. The virtual time-based solution was never adopted and merged.
You will get this:
Rather than this:
Development of the virtual time solution stopped at v5 of the patch as seen here: https://patchwork.kernel.org/patch/11307545/
Looking into the author's history it was also the last thing they've submitted: https://patchwork.kernel.org/project/linux-wireless/list/?submitter=184429&state=*&archive=both