Obviously if we’re on Tesla subreddits, we’re at least considered enthusiasts, so to us we don’t mind nerding out about amperage and kWH, etc. If the average crowd hears this 80% charge limit, they’d not understand it’s for battery longevity, but concluding they bought 300 miles yet they can only use 240 miles to ‘keep the battery healthy’ is inconvenient. That’s why Elon said 90% is fine but not 100%, because otherwise it would show significant degradation, especially if ‘less-knowledgable’ people let the car sit overnight at 100%, and they will have an overwhelming amount of people scheduling appointments to get their batteries checked. Just imagine, we already have the whole ‘displayed range is dropping, is my battery degrading much faster than expected’ daily post, what would we have in addition to that. 90% is grey area and just about gets away the significant degradation portion, but the battery will definitely wear out differently if charged to 90% vs 80% daily for the worst.