“Because that is where Ukraine is? It doesn’t always make sense.”
Your fake hyperventilating for purposes of pro-Putin propaganda is just sheer nonsense. Putin’s putting the Central Military District on combat alert is strictly according to common doctrine. Doing so provides Putin with the flexibility to choose from a number of alternative plans of action.
At the very least, Putin’s combat alert serves to increase concern and alarm among any of the states which Putin may target for Russian offensive operations. This Russian intimidation is used to threaten the Ukraine and anyone who would support the Ukraine.
In the event Putin should currently or later choose to introduce Russian military forces into an overt invasion of the Ukraine or other states, he needs to shakedown the maneuver and logistical units who may sooner or later serve as the strategic second echelon of forces being introduced into the Western theater of operations. A combat alert and exercise does so while providing the added benefit of coercion.
In the event that a full military operation or campaign is undertaken along the fronts of the Western and/or Southern military Districts, the military forces of the Central Military District will be required to reinforce those fronts as the second echelon of forces in any offensive and/or defensive operations. Redeployment from the Central Military District to assembly areas in the Western Military District and/or Southern Military district must be accomplished in the next number of weeks before the advantageous Summer military campaigning weather and road conditions in the Ukraine and elsewhere along the western fronts are ended by the bad weather of the Fall and Winter months.
Not so sure weather is that much of a factor. Russia is the original cold weather attack dog. Putin will move when he thinks the political weather is in his favor, IMO. The USA and NATO (neutered organization) will huff and puff and do nothing of substance. The UN will...well, do what the UN does. Cry.