I just got Ignite with the streaming box and Disney +. Is there any advantage to using this box over my Roku?
I think it comes down to personal preference.
If you have Ignite TV, it's nice that the set-top box can seamlessly integrate broadcast TV and recorded/on-demand content with the streaming services that it supports.
One other thing to consider are the terms of service and privacy policies, and even the business model of the companies whose products you use.