Naïve as I am, but when operating  in the HF bands there are two notable differences between FT4 and FT8. 1) FT8 has a handful of dB theoretical lower noise floor advantage over FT4, and 2) FT4 has an order of magnitude time advantage in being able to complete a 'QSO' in a fraction of the FT8 QSO time (I'm a 'Wham, bam, thank you Ma'am, kinda guy).

Here I am on 20M tonight, short skip is in. No thunderstorms for 800 miles. No neighbors using their 20 year old LCD TVs. No QRN. I have a dipole slung between lawn chairs. On FT8 I can decode as many as 40 stations (most disgustingly loud). On FT4, maybe 2 and occasionally three.

How/where does the 'herding instinct' factor into the preference for FT8 over FT8? There's some basic technical/philosophical/social concept that totally escapes me. I'm a virgin. School me please. Thanks, Bob.