I used to be firmly on the "fake frames" side of the aisle but i've recently changed my mind - with some caveats.
Frame gen still won't do anything about input latency. Its decline with increasing framerate is the main reason why higher framerates feel so good. A 30fps game multi frame gen'd up to 120+fps is still going to respond like a 30fps game.
In more basic terms you could say that if the game felt like shit already, it's still going to feel like shit with frame gen.
However, it does prompt a bit of thinking about what framerates feel "good enough". For many people nowadays, 40fps appears to be the floor. It's deemed a golden number for good reasons, as despite being only 10fps more than 30fps, its
frametime sits between 30 and 60fps:
To me it seems like 40fps is the perfect compromise. In terms of latency, it's low enough to not feel bad for the majority of modern gamers like 30fps does. The only problem remaining is that it can still look juddery.
Even if frame gen does nothing for latency, it works very well at improving motion smoothness. Combining that smoothness with the "good enough" 40fps works really well at tricking your brain into thinking the framerate is higher than it is, because the game has now passed a sort of threshold of acceptability. Nobody is going to turn around and say it's unplayable like I often hear people say about 30fps and nobody is going to complain about judder on an OLED TV.
This post seems more like it's extolling 40fps more than it is frame gen, but I really think the tech only works with framerates above that number. In games i've played where I relied on FG heavily, my brain stops being tricked when the input latency gets too high. There's a weird disconnect between the game starting to feel like soup versus seeing a 60fps read-out on screen (if it's 2xFG then it's likely operating from a 30fps base at that point).
The other thing about 40fps + frame gen is that it makes things like path tracing completely viable on mid-range hardware. You don't need a 5090 to get path tracing in F1 25 or Indiana Jones, and it isn't going to be 19fps.
As long as an appropriate DLSS preset is chosen to hit around 40fps as a base, my 4070 Super performs more than good enough for path tracing: