As someone who took it last year and regrets it, I may be biased. Personally I found that being taught it online made it incredibly difficult to get a grasp of the concepts and maybe had it been in person I would have enjoyed it better.
This goes without saying but it's something you are going to have to dedicate a LOT of study to in order to get a good grade. You can honestly get a 6 with good maths understanding (e.g if you're estimated 8/9 in normal maths) so if the grade you get doesn't bother you and you just want to add another GCSE to the list I say go for it as it is an easy GCSE to pass in my opinion (you only need 20% to pass).
HOWEVER, if you intend to do well e.g 8/9 you need to know the syllabus inside out and dedicate a LOT of time and energy to it. It's extremely hard, the concepts are A-Level ones and it's certainly the GCSE that stressed me out the most. Also bear in mind it will take away from time you could have spent revising other subjects. If you intend to do anything science related in the future I say do it, but expect a long ride. If you're someone like me who's meticulous about how their report card looks at the end and want a full set of 9s/8s be aware that it may not necessarily be in your best interest. I personally wish I hadn't sat it. It was my only Grade 7 ( I got 8x9s, 4x8s and that 7) and every time I look at it I simply wish I hadn't taken in. Final note, the percentage difference between the top grades is insane. Someone can get 50% and another 80% and you'll come out with only one grade difference (a 7 and 8 roughly). A 9 is very hard to obtain (not impossible but certainly hard). Of course, you can always do the lessons and after mocks drop it if you decide you don't like it, quite a few people did this and I think its a good way to not close off the opportunity but also allow yourself to set priorities. Hope all this gives you a realistic idea and that I managed help in some way.