The G9 is a versatile camera - if you want point and shoot, other cameras may do that equally well or better. If you are into manual or customised settings the G9 is a step down from the much more expensive SLR's. There is no bulb setting; a problem if you like to take extended exposures - 15 seconds is maximum (but it fits in your pocket unlike an SLR, without too much damage to your wallet!). Arpeture is manually adjustable to a point, until the camera logic decides that the combination of shutter speed is inappropriate. ISO settings are also selectable.

I don't think the G9 is for everyone as many of the features may never be used. If you take photography seriously, or you have a specific application, it has a place.
To appreciate its features a working knowledge of photography is essential, but you don't need to be an expert. If you like experimenting then the G9 will teach you lots.

I use it for a mixture of applications, having more control over what I want to do. And it works like a charm with Linux, providing you set it up as described.