The way I'd imagine sub-hexes is as a way to define areas and a unit/stack's direction.
More for ease of calculation and improved battle tactics etc. Move is movement on the World map, 1 move = 1 hex, subhexes are free to move around but used for calculating things like direction (if we so decide it's needed or the comic suddenly throws us a curveball - get it?

). You following me? that's how I'm assuming we're using them over in the TT/PnP thread.
some examples from games:
you're using HoMM as a good one right?
So You're saying that you'd have hexes on the world map but not on the encounter map? doesn't sound logical to me, but I'm no coder

Why not have both as this is meant to be TB, but I suppose it doesn't say anywhere that battles in Erf are TB.
Another example is D&D (or most PnP RPGs for that matter)
this is a system that can have any style of map, board or nothing at all but you're imagination! And it can be as turn based as you like

. So say for example a DM has a world map with a marker for the party, this marker can move so far in such a time (usually a day or session) but when the group gets to a town or dungeon they get out a map of the location with a hex grid on it and drops miniatures/models on it, the DM then says: whilst you're here there's no limitation to your movements or turns until an event happens (e.g. going to a specific position or encountering an enemy) then we roll for initiative and play it out by sensible movement and action allowances within the space of a turn and the hexes are used for directional calculations (i.e. sneak attacks and such).
Now that's a very loosely DMed game of D&D but it's much more fun than having a Rules Lawyer for the DM and allows for a good bit of roleplay. But that aside it also sets a good example for how an Erfworld game could run, in my view, maybe with a bit of modification.
M