I would argue that is a Magic Spell enhancing magic directly and not someone just moving really fast to do two things in a single round.
If the Wizard casts a spell that directly impacts the casting and formation of spells, magic, and the manipulation of aether, then yes, it would be like opening a bigger hole in a tank of water and getting that water flow much faster. But hasting a person's physical speed in the physical world doesn't increase his ability to pull magic from the aether more rapidly or allow him to pull water from a small opening twice as fast because he moves his hands twice as fast... the water flow is the same rate.
Haste is haste. Considering the Wizard appears in RoCo
V and considering reaction speed (implying thinking speed) isn't just "physical speed" (not in the way you apparently consider it), I think it means someone thought, after quite a long time, a distinction should be "officially" made, meaning the answer wasn't so obvious. As for the "physical world", everything is physical, including thought processes that are nothing more micro-electrical signals in the brain, or in this case "magic (pulling) from the aether" that manifests in the physical world anyway. Haste is haste. Nothing in the RAW but balance says that haste only provides "physical" haste, as it's describe in meta-game mechanics, giving a character 200% activity. In fact, even the spell (RM2 edition at least) clearly says that rules about the matter (section 7.4 in my SL copy) are "
suggestions for handling this", and a note clearly says that "if a GM is prohibited the casting of two spells in one round, as it is
suggested" ...
Now, obviously, a GM may change rules as he fits, but, here, even the rules remind you they are merely suggestions about how to handle haste when applying to spells, and not hard rules.