Definitely. OnionShare requires your own computer to be connected to the interwebs - the data is only accessible while your OnionShare app is running. With Arweave the hosting is taken care of (the data/website/etc is hosted on the Weave). Plus, OnionShare sites are not verifiable/ reliable as they are a website running on someone's computer. An Arweave site is timestamped and unforgeable; it's also resilient (replicated on many nodes) and permanently stored.