Yeah, the Total War series does this. Multiple different unit sizes so you always have up to 20 units per army, but the number of soldiers per unit varies between 40 and 200. I would prefer this for BFGA2 as well as I know my computer could handle bigger battles.
"A few second" is like that time, 40-60 seconds i think, it's pretty useful especially early game in the campaign for Space Marines before you get the ability to run silent with Strike Cruisers. Just activate it before getting into view range and you are able to close to boarding range before the enemy is able to identify you. It's also great if you have to run after boarding, trigger it and the enemy fleet won't be able to fire at you while you make a run for it.
Also there is a visual effect on the enemy ships, little sparks.