The reason of Corporation Internet Filing.

The Canadian Government spends a lot of effort with providing Canadian corporations an secure, easy-to-use, confidential and convenient options for electronically filing corporation income tax return.
In support of sustainable development, a paper copy of corporation tax return is not needed.
This way CRA can reduce a processing costs.
Corporation Internet Filing streamlines the tax filing process and bring to the corporation an immediate confirmation of receipt and fast results of refunds.

cra-arc.gc.ca