I read into this a few years ago and I'm not entirely sure what to think.
One thing I read was that the creepy guy who was exploiting Britney at the time of her breakdown - Sam something? - had a lawsuit against her, and part of the reason it was in her own interest to have the conservatorship continued was that it stopped her being sued by him.
But in general, I feel a bit conflicted about it, because I actually do know someone who would really benefit from an arrangement like the one it seems Britney has. Basically, severe mental health problems, able to live a relatively 'normal' life while on medication and given support, i.e. could hold down a job if supported but if left to manage own finances would quickly go off rails. Has been committed on multiple occasions but essentially is court ordered to go on meds, stabilises, is released, can't be court ordered to keep up meds because is deemed to have capacity as a result of the meds but then immediately comes off them, is ok for a short while then starts struggling to manage finances, abusing drugs, etc etc. V vulnerable and open to exploitation.
I have often thought how much they would benefit from a set up not unlike this. And I actually don't think the amount of money the father is taking is outrageous, 100k a year wouldn't be an unusual figure for a manager, probably on the low side given her wealth. If he is actually stealing lots of her money its obviously different. The idea that she was committed 'for getting a burger' without her fathers consent but then the sentence say also 'stopping her medication' ....
I never realised how complex mental health conditions could be, or the extent to which some people will never fully 'recover' in the sense of being able to lead a fully independent life, but there are limited structures to support most people. I think its not outrageous to imagine a talented singer might be able to sing and perform while given a lot of support, but still not be able to be fully independent safely. I don't think its at all as black and white as 'completely unable to function or work' and 'entirely capable of having a career and managing your own affairs.'
I really hope Britney isn't being exploited, I have a soft spot for her. Its hard to tell from the information available, but I think it isn't impossible this is being done with her wellbeing in mind. That being said, you'd hope there were independent healthcare professionals overseeing it, especially given how long it has gone on for.