The thing with DLC is success on it is subjective but even if as DLC the Pearl Jam efforts were hit and miss... Ten sold by the bucketload and then some but the second album we got licensed as DLC on the back of such a well recieved DLC effort sold a fraction of the sales compared to Ten.
As you said live tracks could further negate the appeal so a disc release would bomb. If HMX have indeed already licensed the tracks then why not release them... they will already have made all the arrangements and financially pot commited themselves so there is no harm in getting something in return. The majority of the tracks after all fresh efforts from the band not already on the platform but we shall only just have to wait and see for what HMX has planned for these.