With all due respect, I don't believe aphantasia is a real thing. The way people imagine things is so varied, weird, strange, and unique that I don't think it makes sense assigning labels

Labels should always be used with caution, but for me, learning about aphantasia led to me reconsidering the ways in which I imagine things, and this had a beneficial impact on how I communicated with people close to me. For example, I seem to be an odd mixture of relying on visual stimuli for thinking (so I have visual reminders all over, and reading complex info is way easier for me than hearing it), but also seem to lack the ability to visualise. This means that if my partner asks "hey, do you remember which drawer the mini screwdrivers are in?", I would usually be unable to answer, despite being able to walk in, take a glance at the drawers and go "that one, there". We didn't realise how frustrating this was for both of us until we reflected on the possibility of me having aphantasia. Whether I do or not doesn't matter. More relevant is the fact that now, when he asks me questions of where things are, it'll often be accompanied by a photograph of the location, which drastically improves my ability to recall and point to where the item is.

To some degree, I agree that it's nonsense to assign labels when in nature and in humans, variation is the norm. Certainly it can lead to reductionism and ignoring wide swathes of that variety if one is on a quest to sort people into boxes. However, there is still a lot that we don't know about how the brain works to process things and labels can be instructive either in researching aspects that we don't yet understand, or for regular people like me who find benefit in a word that helps me to understand and articulate that there are ways that my partner thinks and processes information that seem to be impossible for me to emulate. "Aphantasia" helped both of us to be more accepting of these differences.

Framing a phenomenon as either real or not isn't especially useful though, largely because of the ambiguity in the phrasing. An example in a different domain is that I've seen a wide variety of people claim that they don't think autism is a real thing. This tends to be received as offensive to many people, not least of all autistic people who feel like their lived experience is being directly attacked and questioned. Sometimes it is, and their anger is justified. However, I've also seen the "autism isn't a real thing" sentiment come from (often autistic) people critiquing the label and how it's used, especially in a clinical context. They argue that it perpetuates a binary framing of autistic and not autistic, which further marginalises people who do have a diagnosis, and isolates some people who have autistic traits but are overall sub-clinical in presentation (who may have benefitted from understanding these traits from an autistic perspective). Regardless of one's view of the arguments, it's pretty clear that these are two very different stances that might be described by "autism isn't a real thing".

I make this example because debating of the utility of labels can be a great and fruitful discussion that helps to improve our understanding of the underlying phenomena and people's experiences of them. Framing that debate as what's real or not can lead to less productive arguments that are liable to cause offence (especially on the internet, where we're primed to see things in a more adversarial manner)