Yes, these red-eyes to Korea and Japan have been quite popular for a number of years - way before the pandemic already.

Even if I take the earliest morning flight out around 8am, I'm not going to get much sleep the night before either. With the 1-hour time difference, I arrive just after lunch, For Tokyo, I pretty much lose most of the day by the time I reach the city from Narita. So I can sympthasize why the short red-eyes are so popular to maximize the time in Japan.

I haven't seen my friends try to do a short weekend hop to Tokyo or even Osaka though. That sort of trip is more for Taiwan or even Bangkok. Japan is usually worth a much longer stay!