As blopeur said in another reply you need to feed data to the supercomputer, and as parallelizable as your algorithm may be some data might need to be shared between nodes at some point, just to name a couple of examples.
If you connect a lot of cloud instances to act as a giant distribute computing cluster they’ll receive/share/return data via network interfaces or yet worse the internet, this is really really slower than what super computers do.
For many applications that solution would be more efficient than a supercomputer, but for applications that need a supercomputer it would be inefficient. It just depends on what you need to do, but in any case it would be a computing cluster not a supercomputer.
If you connect a lot of cloud instances to act as a giant distribute computing cluster they’ll receive/share/return data via network interfaces or yet worse the internet, this is really really slower than what super computers do.
For many applications that solution would be more efficient than a supercomputer, but for applications that need a supercomputer it would be inefficient. It just depends on what you need to do, but in any case it would be a computing cluster not a supercomputer.
(my two cents, I’m not into that field)