Well, it's not.
Their inability to hit and run utterly destroys their viability at that early stage. Skirmishers may only do 1/2 the damage to heavy infantry (and only 35.7% to light infantry), but they can hit and run. They don't have to stand there and take damage. Even though they cost more, and do less damage, they end up being more cost effective.
You also don't need to worry about pop space so much or to send Dance Hall early on with Skirmishers.
But ...
When you're in Fortress, and you'd using those beautiful 5.2 speed Halberds, that's when it is actually a good time to start training Renegados.
The biggest threat to your Halberds will come from light infantry with a substantial HEAVY infantry meatshield. Think Janissaries and Abus Guns for example. You'll need to cut through those Jans to get to the Abus, if the Ottoman player is smart.
But wait, you think, don't I now have access to Veteran Skirmishers? Don't I have access to Counter Infantry Rifling at the arsenal? Yes, you do. But consider the following:
You need all the food you can get to mass Halberds.
Veteran Skirmishers deal 36 damage to heavy infantry.
Veteran Skirmishers with CIR deal 54 damage to heavy infantry.
Assuming you even used the Combat Card, those numbers change to 40.5 and 60.75.
Renegados? They deal 60 damage to heavy infantry and 40 damage to light infantry.
As you can see, training Renegados frees up your food. You don't need to get the Arsenal and research CIR.
The high base damage also means that once the Janissary meatshield is clear, your Renegados also deal good damage to the Abus Guns themselves (20), unlike the Skirmishers (9 or 10.125 with the combat card).
At this stage, once you're engaging with Halberds, you no longer require hit and run. You just need that Janissary meatshield removed ASAP. Especially if it is also protecting Falconets that your Halberds are trying to get to.
Thus HERE is the time to use Renegados.
There is one exception, though. If you have Jaegers available at the Saloon, then researching CIR and using those makes more sense. These babies will deal 90 damage a shot to the Janissaries and 15 to the Abus Guns. A more than acceptable tradeoff.
Other than that, go nuts with the Renegados. Except you don't even need that many. Just 10 as support will do an excellent job. And at this point you can actually afford the pop space for them.
They will also do a good job of fighting swarms of individually weak light infantry, such as Macehualtin or Strelets, against which Skirmishers really suck. It's the base damage difference. With 10-15 Renegados backing up your Halberds, you will even cut through these light infantry swarms with your Halberds.
And since you have the Saloon up anyway, throw in some Merc melee cavalry for extra fun, if they're available. And hey, what do you know, if the enemy has any ranged anti-cav or Eagle Knights, your renegados will annihilate those too (60 damage a shot too them as well). Convenient, isn't it?
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