In my opinion ETNs are no different than owning stock. ETNs can be recalled and drop in value just like a stock can be wiped out by a company filing bankruptcy. I have been doing this a long time and have owned three companies that filed bankruptcy. I didn't receive ANYTHING for those shares from the bankruptcy court. Any security on the US stock market can go to zero. I am usually more concerned with the management team or financial history and strength in whatever I decide to invest in or trade. Credit Suisse seems to have a good history with their ETNs so I have bought their ETNs to have a monthly income. Good luck in whatever you decide.
On edit: USOI had a new 52 week Post pandemic high of $5.23 today.