Turkey has an automatic build (bulgaria) and a claim to two (rumania and greece) that are disputed between two other nations each (russia and austria, italy and austria), all very vulnerable. Russia for its undefendableness, austria for it's centrality, italy for it's unwieldiness. If turkey gets both it's armies out of it's own soil, it is a terrible power to be reckoned with.
Nazim Karaca aka the Red Sultan.
What's the fastest route for an army to get from Constantinople to Armenia and back? Through Ankara? Don't neglect to notice that the route through Smyrna is just as fast. Smyrna borders every single land province that Ankara borders, plus Syria. An army in Smyrna rather than Ankara lets you keep open two options:
Those are small points of strategy rather than big ones, aren't they? Good players pay attention to the small points. Generally speaking, Smyrna is the superior military route from Constantinople to Armenia and back.
In a game between skilled players, army Smyrna is the one unit on the map likely to hold quietly in place in Spring 1901. Why? Assume that the Turk intends to open to Bulgaria and bounce the Black Sea. An inexperienced Turk always lets army Smyrna follow to Constantinople. An experienced Turk, however, realizes that his Bulgarian army will get blocked in Bulgaria in the fall, unless the Austria happens to be friendly. Army Smyrna to Constantinople is blatantly anti-Austrian, isn't it? Such a move is unlikely to produce a friendly Austrian. A Smyrna army in Constantinople will have nowhere useful to go in the fall, will it?
There may be other reasons to open to Constantinople, naturally. What reason is there for you to hold army Smyrna in place, when you open the Turkish position? There is one big reason: Russia might stab you! You never know. Diplomacy Russians love to get rid of Turkey, quickly and quietly, if they think that they can get away with it. Army Smyrna is effective insurance against a Russian stab, isn't it, but only if it's still at home in Smyrna!
And what if you want to stab Russia? You might, if you're a Turk. It's usually good to keep your options open, when you can.