Ha ha - a mate of mine used to work in a bike shop and he always did that with the chain segments left over from chain replacements - he didn't have to buy a chain the whole time he worked there!
Still, the other points still apply - a drooping chain, and needing to replace more links, less frequently.
How about smaller chain ring and smaller rear sprocket? now that would save chain lenght and you would collect the bits for the free one faster.