Hey Benjamin,
Thanks for reaching out to us!
Yes, the ticketing systems can be used together for an event, however they cannot be used to manage the same tickets for an event. So, if you have a general admission ticket for an event and have 10 to sell you could not create a single ticket with “10” stock availability to sell between WooCommerce Tickets and Eventbrite tickets. The inventory is not synced between the two systems.
If you wanted to sell only 10 tickets between the two systems, you could create an Eventbrite ticket with 5 available tickets and a WooCommerce ticket with 5 available tickets. Stock levels for tickets are managed by the processing system that you choose to use. In this case, the WooCommerce tickets would have stock management controlled by WooCommerce while the Eventbrite tickets will have their stock managed by Eventbrite.
Let me know if this helps.
Thanks!