Revenue is not informative at all because there is no indication of profit or loss. I could setup a business tomorrow selling $10 bills for $1 and my revenue would be through the roof. I'd also be bankrupt.
Revenue is not profit and is meaningless. They may as measure Xbox performance on the number of salads were consumed in the canteen that quarter.
The question of Xbox's profitability continues to be unanswered by Microsoft. This itself speaks volumes. You shout and celebrate good numbers, conceal others.
You wanted to know the "relevance of gaming to the company". Xbox revenue, at it's current state which is limited to XB1 & 360 hardware and software, is about 70% of Sony's Game & Network Services segment. Sony sold 3.3 million PS4s which is %200+ higher than number of consoles that Microsoft managed to sell (XB1/360 combined) and enjoys from PS4 hardware cost reduction at the same time (according to their report, which should be true for XB1 hardware, but it priced 50$ lower than PS4), yet Xbox managed to make 70% of Sony's revenue from G&NS segment. So, how exactly you expect Microsoft to loss money on Xbox? 43% of Xbox revenue comes from Xbox Live transactions & 1st-party games.
Also Microsoft reports are different than Sony. They don't mention operation income or net profit for each segment (which is different from Sony's approach).