Why are crawl spaces so narrow?

[MaxP779]

I found a hatch in the cupboard under the stairs, its next to the electric meter and water turn off thingmy. It is very narrow though, a small child would likely have trouble going in there, what's the idea behind this? Seems a bit pointless to have any space at all no?

House was built in 1997.

 

[MaxP779]

Nah its just some of the plywood thats been cut into a square, yeah access panel would be a much better term for it. Ill post a pic when i get the chance.