Ace only plays music via BT from any source, or the included cables directly connected to the source, only wifi use is using swap from arc, so unless you choose the music from an app on you tv and using the arc you won't get music via wifi , In any case you won't be able to play music from the Sonos app into the Ace.
Just to also add, the Sonos App is not a music player, it’s a ‘remote’ to configure and control Sonos products. The music plays from the chosen source direct to Sonos speakers over the local network. In the case of the Sonos Ace, it does not connect to the local network, it uses a Bluetooth connection instead, so playback via that App is currently unavailable. You ideally need a ‘player’ App instead installed on a device that has a Bluetooth connection to the Ace.
There are ways however to playback ALL audio sources from the Sonos App to the Ace in an ‘indirect’ way, but it can be quite expensive to achieve this. I actually do this by using a Sonos Port and its S/PDIF digital coax output linked to a Fiio BTA30 Pro Bluetooth Transceiver, set as a TX.
It allows playback from the Sonos App, such as Sonos Radio, for example, to the Port and in turn the audio is output to the Fiio BT TX. The audio sent, is transmitted using Apt-X HD codec to the Sonos Ace and provides really good quality audio. I already had the mentioned hardware prior to getting the Ace, but, as mentioned, it can be quite expensive to do these things.