Radiators are not aircooler heatsinks. There's a huge difference there. With a rad, it's all about the coolant temp, which is absolutely not the same thing as cpu or gpu temps. Just because the cpu is 50°C, does not mean you will see 50°C at the radiator. With a radiator it's a constant battle with ambient temps, either case ambient for exhaust mounted rads or outside ambient for intake rads.
With 50°C cpu, 23°C outside ambient on an intake mounted rad, you'd be looking at 32-35°C coolant. That's all. That's what the fans are blowing into the case. Not the 50°C cpu.
Inside the case, ambient temps with an air cooler, exhaust mount rad, or basically any setup generally run 6-12°C above outside ambient, simply due to heat from various sources like Northbridge chipset, ram, gpu, Sata controller chipsets etc. So with a 23°C outside ambient, you can easily expect case temps to run @ 29-35°C.
Adding 32-35°C air from an intake radiator to case temps that already run 29-35°C doesn't make a damn bit of difference. You aren't magically dumping excessive hot air into the case, heating everything up.
It honestly changes nothing to any real measurable degree.