Over the years I have been subscribed to various MMORPGs for a long time, but that doesn't necessarily mean that I have played them every day during that subscription period. If you don't have much time, starting up a MMORPG usually doesn't make much sense. These aren't games that usually play well in chunks of 10 minutes, as they are designed to be relatively time-consuming. Warlords of Draenor is a big change in that respect: On a day where I don't have the time to play World of Warcraft, I would still log in for 10 minutes, twice a day.

The reason for that is the garrison sub-game, which is principally based on real time, not play time. You have a garrison cache which slowly accumulates up to 500 garrison resources, at a rate of 1 resource per 10 minutes. You have various building where you can give 7 work orders per level of the building, and each work order takes 4 hours. And you are sending followers on missions which last from 30 minutes to 10 hours. If you don't log on at all for several days, first your followers are all unemployed, then after about 3 and a half days your garrison cache reaches its cap and all the work orders of even level 3 buildings are done. At that point your garrison stops producing anything useful until you log on, send out your followers again, empty your cache, and start new work orders. Oh, and in addition your mine and herb garden spawn resources once per day.

If the reason that you don't have time is that you are working long hours with no access to a gaming computer, which is a likely scenario for an adult, you can still log in once before work and once after work and get pretty much everything set up again in 10 minutes each, shorter if you don't have alts. At this rate your garrison resource production is always at maximum, and by preferring long duration missions even your followers are productive for most of the day.

As I said, MMORPGs are generally designed to be time-consuming. At the level cap you usually need to put in quite some time to achieve some reward that is still useful for you. Compared to that the reward payout of a garrison per hour of play time invested is pretty fantastic. The downside is that by playing more, you can't advance much faster. For example it takes 1,200 resources to upgrade a barracks to level 3. With the garrison cache, lumber mill, and trading post you'll get those resources in around 3 days of just waiting around. But if you decided to get those resources by farming rare spawns, you'll get only around 15 per rare killed, and would pretty much need to kill every rare spawn in the game for one upgrade. Add all the treasures and quests that give resources and you'll have another building upgraded, and have run out of options.

To somebody familiar with city building / village building / farm building games on mobile platforms like The Tribez or Hay Day, that 10 minutes, twice a day mode of gameplay will be very familiar. But then these games don't have a subscription. While I would consider having to wait for hours for progress to be better than having to grind trivial content for hours for progress, the question is nevertheless how good this model works for World of Warcraft. 10 minutes, twice a day, makes 10 hours per month, which at $15 per month seems pricey. So the garrison is unlikely to be the sole reason for anybody to keep on playing. Even if you can get epic gear and other rewards for your character, those rewards aren't doing you any good if you don't play that character. But for a "weekend adventurer" with little time during the work week, the garrison is certainly a big plus.