You get to have an opinion that is not fully informed. More of an awareness of what others thought about it. A slightly educated guess about it. No it shouldn’t be taken very seriously.
This came up once in a thread discussing Poor Things with someone who had not seen it giving the movie a very negative evaluation, arguing with those who had seen it about what the movie was. I considered that review bombing and was moderated for saying that. Several here argued that opinions based on hearsay and speculation were as valid as opinions based on experience of the actual thing.
You should read it yourself if being able to critique it meaningfully is important to you. I’ve no idea why that would be the case. Knowing what those similar to you who have read it think of it is enough to decide if you want to read something.
I have heard it is not a great book. My mother in law liked it and that suggests to me I wouldn’t. My daughter thought it was okay as a trashy fun thing and knows my tastes and says I’d not. But some people clearly enjoyed it.
My contribution to any discussion of it is worth very little.
ETA. I was Pitted for pushing back against the sight unseen beating up of it actually! You were part of that discussion. Same subject really.