I have personal and professional experience in this.
Part of it is just the 'look' of the epoch.
Some of it is admiration or appropriation of how African and Latina women look (filtered via people like the Kardashians).
Some of it is peer pressure. Some of it is for how it looks on social media. Some of it is for current makeup trends.
I'd say most are under the belief of that because fillers wear off, they can go back to 'normal' at some point. But overfilling can and does harm the lips and facial contours, I've seen nasty haematomas and dead tissue from poor technique or back street off the back of a lorry fillers.
Trust me, good filler work is not noticeable at all. It should be used to give a little youthful 'pep', 0.5 to 1ml usually enough. Losing the definition of the cupids bow or vermillion border is sloppy work. The DSL look for a date or pictures should then be done via makeup, bee venom cream and/or plumping (ie little suction devices)
And like with any other beauty treatment, aiming for more than '10 years younger' is a fool's errand.
