Why is the Mopar Performance P3690731 voltage regulator "race only"?

[MaximRecoil]

This is from the Mopar Performance catalog:

VOLTAGE REGULATORS

F. Voltage Regulator, Constant Output

To ensure your ignition and electrical systems can provide maximum
performance, install a Mopar Constant Output Voltage Regulator. Voltage is held
at a constant 13.5 volts. For race applications only.

P3690731 Voltage Regulator, Constant Output, 1970 and Newer V8,
Race

Constant output seems like a good thing (especially in my case, since I've been trying to solve a rapidly-fluctuating voltage issue in my car for a long time), so what's wrong with using that regulator in a street car?

[Canadian1968]

Is this the electronic voltage regulator , that is connected to the Alternator?

[Canadian1968]

I belive it has to do with the load that it would put on all the other parts of the ignition system , during cruises or DD .

[John_Kunkel]

Always wondered that myself, constant 13.5 volts is below the normal that I see which is more like 14.2-14.5 volts.

Under high load and low rpm (I don't see that as normal race conditions) it might drop down closer to 12.5 volts, maybe the constant output will maintain 13.5 volts under those conditions. Never used one so I dunno. 

[Bronzedodge]

I have read that the constant output regulator causes shorter bulb life in the whole car.  Enough to the point that it's a problem.   No personal experience.

[John_Kunkel]

What we routinely refer to as 12 volt bulbs are actually listed by the manufacturers as 14 volt bulbs and most (all?) components in a car will run continuously  at 14 volts.

[MaximRecoil]

Maybe the problem is that 13.5 volts is too low to charge a battery:

To charge the battery, the alternator voltage output has to exceed a minimum charging voltage. This minimum charging voltage is 13.8 volts dc across the battery terminals, or at the output of the alternator. A single lead-acid cell starts to charge at anything over 2.25 volts. Since a 12 volt battery has six cells, any 12 volt lead-acid battery needs at least 13.8 volts to start to charge. This voltage will be enough to fully charge or maintain the battery on a trickle charge, but charging time will be very long at 13.8 volts.

To fully charge in reasonable times, alternator output  must be 14.2 V to 14.5 V as measured right across the battery posts. Above 14.5 volts charging voltage, batteries have a greatly increased tendency to release excessive acidic vapors, hydrogen gas, and to corrode things around the battery.

https://www.w8ji.com/battery_and_charging_system.htm

If that's the case, what makes 13.5 volts suitable for racing? It seems that keeping the battery charged would be important in a race car that presumably has a power-hungry high-performance ignition system. It wouldn't matter for drag racing, where you're only racing for several seconds at a time, but for e.g., NASCAR type racing it would matter.