See this is the problem, you can fake it yes. And you can get
excellent even jaw dropping results. Case in point? AC Unity's GI, which imo is as good as any ray traced GI, hell they even managed to fake the look on some dynamic objects using small probes for stuff like character lighting etc. But in the end it did mean the game doesn't have a dynamic TOD and the Devs have to spend a lot of time micromanaging the assets plus wait for the baking process anytime they want to make a change.
Or how about thr room in UC4? This is equivalent to ray traced GI, but ever wonder why other parts of game don't look like this despite the game not having dynamic TOD? It's because it's a lot of effort and not really feasible for anything other than a small pretty much non interactive environment.
Then there are more dynamic implementations of GI using probes, but hen these probes themselves are pre calculated. So it's more like instead of switching between 4 high quality variables like AC Unity, they dynamically switch between 6-8 variables throughout the day. The limitation here being light has a lot more variation and properties throughout the day than 6-8. And since it's precalculated it doesn't consider variables such as dynamic clouds (which games seem to use a lot). So you could have situations where there's cloud over but the room is still lot like it's clear day. And again, as with the previous method this one requires even more micro managing and wait time to generate all the light data.
So yea we can get results that look as good without ray tracing, but at what cost? Cause the moment something is done on large scale, or something moves...it breaks, and it still requires a lot of time to be spent on making it work. With ray tracing GI you get a one solution fits all implementation, you deploy it and it is global...for all TOD...at all times...for all objects. No need to spend time micromanaging stuff to make it look good under all variables, always a guarantee to work on every object dynamic or static under all lighting conditions, and most importantly....no need to wait for generation of pre computed data effectively speeding up development. It streamlines the process so much and it's physically accurate to boot. This is why it's the holy grail of computer graphics.