raylib is good for starters but there will come a point where you'll just have to write shit yourself.

1. The batched rendering chokes hard real fast so even for basic stuff like a tilemap you'll end up having to do your own VBOs if you don't want garbage performance
2. It lacks some basic things out of the box like stencil functions, raysan considers that too "advanced" despite being dead simple to add and use.
3. Audio module is lackluster. If you don't want fine-grained control it's probably fine but I just ripped it out and did the miniaudio handling myself
4. stb_truetype is lightweight but looks like ass, you'll want to replace it with freetype

I don't have many examples because raylib doesn't actually do that much at least for 2D (I know that's glossing over everything else like input but I think in the end graphics matter most). I understand why people call it a toy lib after using it, but the convenience of getting right into it is a plus. If you're decent you'll want to drop it and I can't fathom using it for 3D but someone else can comment on that.
Anyone saying you can't use it for a serious project probably mean using it out of the box, and yeah they'd be right, but it's not like the entire thing is fucked or anything.