Can confirm, will destroy the rubber/plastic bits in your toilet.
That being said, I still use them all the time and replace the toilet innerds after a few years. I just would rather clean the toilet every few months and replace toilet parts every few years than clean the toilet all the damn time and have old working toilet parts :shrug:
Sometimes I wonder if in 75 years people will look back on our caffeine use in this generation like we currently look back at cocaine use in products in the 19th century. Until then, I continue to slurp down coffee like that is my actual job.