In your particular case, the only reason to go APS-C is if you can't afford the RP (+ EF lens adapter) + 17-40mm. (And since the 17-40mm is on sale right now, I would strongly encourage you to try to swing this option.)
More generally, another consideration for others would be if they would be using EF-S lenses (which are often, but not always, cheaper, smaller and lighter) or EF lenses. Because, if using EF lenses on an APS-C body (which is also often, but not always, cheaper, smaller and lighter than a full frame body), they won't be getting the full benefit of a cheaper, smaller, lighter package.
But in your particular case, either of the EF-S lenses mentioned in the other post will serve you well, and in fact, better than any EF lens will on an APS-C body.
P.S. and as long as I'm posting, IMO the 24-105mm f3.5-5.6 is a non-starter because 1) it's nowhere near as wide as the 17-40mm. 2) when you add the adapter, it's longer (physically) than the RF 24-105mm f4 is. 3) the RF (and EF) 24-105mm f4 is a better lens. 4) the RF (and EF) 24-105mm f4 is a stop brighter at the long end (zoomed in). 5) the RF is a native lens, meaning it has the control ring, which the EF lenses don't.
I am trying to choose my first camera but I don't know if I should get a full frame or one with a APS-C sensor. I know that the main difference is the crop factor and for this reason I would go full frame. The problem is that if I choose a full-frame camera I would need to spend more for the camera itself and also for the lens, so the question is does it really worth to choose a full frame over a APS-C??