Landscape lighting (Malibu)

I want to buy a 300W Mabinu transformer and hook up maybe 5-6 50W spot lights.

You know the heavy transformer with a dial (timer) on it and it cost almost $100.

It says you have to put the transformer outdoors. Is there any reason I cannot put the transformer indoors?

Also the landscape voltage wire is DC low voltage, can you go run the wire into a crawlspace vent , thru the crawlspace, and out to another spot?? I have mostly concrete slab around the house and no dirt to bury the wires.