Neither bad option. I'd rather have the 24-70 f4 or 24-120 f4 + a 35 1.8 as my primary 2 lenses though for the same cost. If I shot weddings or fast moving events, that would change.
For me it's more about the "look" of the image wide open of a 35/50/85 1.8 though (take your pic), which can't be replicated.
Secondary is the weight, the 24-70 2.8 is much heavier and larger. Yes, the primes in total might weigh more, but they don't when mounted on the camera... Addding another prime or two in my backpack (or leaving it in the hotel room) doesn't feel like anything, but you feel it in your wrist after a few hours, and people will notice you more with a 2.8 zoom mounted if doing travel or street photography. Take a 35 1.8 with 62mm filter at 370g mounted vs the 24-70 2.8 with 82mm filter and 805g mounted...quite the difference. Throw the 28 or 40 on...even more so.
Third, I prefer shooting primes and the way it makes me shoot and think, the 24-70 f4 is a complimentary or situational lens to my prime trio.
The IQ of the zoom lenses are fine, the high ISO performance is also really good.