Read the fine print.
When I was looking at licensing, on-demand was much more expensive than a local network license (maybe it's only "free" during the first year?). It'll require Internet access to work. Finally, they told me that the network license we got is supposed to be used only at a single "site", so while ethical, sharing a license to a remote person may be against the terms of service...
I don't see any good reasons for your to go to an on-demand license...