There's a webshop (maybe several), a WMS, a PIM, payment providers, marketplaces, suppliers, a BI environment, a 3PL partner, and probably one more system that someone once said was temporary. That doesn't have to be a problem. In fact, we're firm believers in best-of-breed.
Use a specialised system if it's demonstrably better at something than Odoo. But then make sure the information flows cleanly through your organisation. That's why our Odoo Gurus don't just look at the connection itself, but at the whole process around it. Because getting two systems to talk to each other isn't that hard. Making sure they still understand each other in three years' time: that's the real skill.