I think in terms of features, JIRA integration would be impressive and make me switch and could make it sticky enough to pay something. Those integrations would be:
* For a pointing session, show the title and description of the JIRA. While a simple feature it would be very useful as you um and er about the points to quickly re-read the description, even though as a team we have talked about it alot already.
* Save the points into JIRA - obvious one, saves that extra click or two!
* Show some examples of each of 1,2,3,5,8 etc. points. These could be shown as cards with titles only for compactness, but then when you click you are taken to the JIRA, or even better pop up a compact popup with the details (JIRA is slow, so if you cache those specific example you make a nicer UX)
* Allow some shared notes to add summary points. E.g. "Bob when from 8 to 5 once he realized the API already supports batch updates".
Again as per "mum test" you could implement these and I personally wouldn't turn around and pay. Because that is just what it is like. But I think these are features to consider, you could do more research to see if they become selling points or not.
Good luck!