[Alneyan]

That, and an Organic ship needs to survive one turn to see the regeneration kick in, while the Crystalline effect will work after each and every hit (well, barring weapons bypassing armour or shields). So the Crystalline armour is much better if your ships aren't expected to survive one turn, where their regeneration ability might improve the odds of the rest of your fleet.

Putting more than 10 Crystalline Armours increase the number of hits you can take while keeping your maximum regeneration ability (you cannot shrug off more than 149 points of damage, regardless of how many Crystalline Armours you have on board the ship). So, having 20 Crystalline Armours would require the attacker to destroy at least ten pieces of armour before breaking the "improved Emissive Armour" effect of the Crystalline Armour.