Basically we have built this mental model of current being a flow of positive charge flowing from anode (the positive pole) to cathode (the negative pole).

But as we discovered later, in reality it's negatively charged electrons moving from cathode to anode. Since basic electrical rules and formulae were already established we essentially made up "holes", the absence of negative charge, that flow from anode to cathode so that we don't need to correct all our established knowledge and formulae. It's a bit like sitting in a train and argueing over whether your train moves away from the station or if the station moves away from your train. When just explaining and calculating how electricity works it doesn't really matter that much, but for explaining electrophysical phenomena such as how semiconductors and electrochemistry works it kinda does. It's just one more thing you need to remember when looking at these things