8 GB on an M1 or M2 is not the same as 8 GB on an Intel-based device; the memory bandwidth is significantly higher. A 2x factor (Apple Silicon 8/16 GB vs Intel 16/32) seems about right.
The RAM that is available is faster and the SSD is also quite fast, but it's a little bit misleading to claim that an Apple Silicon Mac with 8 GB of RAM performs similar to an Intel Mac with 16 GB RAM. The Intel Mac will actually almost always perform worse and run hotter with CPU-heavy (but not memory-constrained) tasks, no matter the amount of RAM it has. But if the Apple Silicon Mac has to read / write constantly to and from swap and the Intel Mac doesn't (assuming whatever you do doesn't require an Intel Mac with 16 GB of RAM to swap), you will still notice a difference.
Overall I would still prefer an Apple Silicon Mac especially if it's just for testing purposes. It's not like one Electron app will require constant swapping. An M1 Mac mini with 8 GB of RAM is perfectly fine for that.
Under many circumstances, even most, this is generally true-ish. However, experimenting with Stable Diffusion in recent weeks has shown me that when you need to load something in memory that's greater than 8GB, only physical memory greater than 8GB will do!
