Concern using httpd_ws_send_frame_async

[ss_flashina]

Good afternoon!
I set up a webserver on an ESP device, to wich someone (a laptop) can connect and perform an OTA update. To be able to visualize a progression bar on the webserver, I send the current percentage using httpd_ws_send_frame_async, but I saw in the API that This API should rarely be called directly, with an exception of asynchronous send using httpd_queue_work.
Is there a motivation why this function should be called rarely? I haven't seen any memory leaks or any problem in my code, but I'm concerned.
Moreover, if I try to use the function in combination of httpd_queue_work, I see that the function is correctly queued but never executed.
Has anyone a bit more experience to explain this to me? Thanks a lot!