Well it means nobody can avoid their extortionate upgrade pricing anymore so I think that decision paid off well for them.
The first thing I used to do when getting a Mac Mini was ripping out the memory and sticking in the max I could get. For a fraction of Apple's price. Some of them even had more memory than Apple offered itself.
I know there are also benefits to the soldered memory like the huge bandwidth but still. That matters mainly for very specific workloads like LLM inference.
No one's really big enough to get stable pricing on memory except ai firms and Nvidia.