Trading view is a neat platform to quickly look up various asset price levels, assets your broker might not even offer subscriptions to. Example, DXY us dollar index can be quickly looked up. IB does not offer access to that index unless you subscribe to the quite expensive ICUS feed to see DXY futures.
Then it's a solid backup tool in case your broker data are unstable.
Also, imagine you are logged into your IB account from your desktop computer but you want to quickly check market prices on your mobile while away from the desk. You could still log into IB from your mobile but then you get logged out from your desktop machine. Not a big issues but an inconvenience when all you want is check a few price levels.
This is how I use TView. Not as a serious trading assistant but as a workaround for minor inconveniences.