that is probably being suggested because it’s what Zhea Erose did, she did a lot of voice practice playing Counter-Strike online and made dramatic progress in that time.

She’s so influential in the trans voice training scene that I’m fairly confident that’s the reason this advice is shared. To be honest, I think it’s good advice if you have made enough progress on your voice, and yeah, assuming you have a thick skin and are looking for earnest impressions of your voice.