Last night I was doing Dispatch Missions until I ran out of them. Then I saw another tab: Dispatch Missions (online). I sent my dudes (units) to do two of them, and the time it said it would take was like a day and some hours. I said why not.
Today I log in and find a new batch of Dispatch missions (offline), but I can't get to them because the my units are still preoccupied with the online ones. So then I have to go back to see the progress, and you can "hurry" them along by paying MB coins. F- that.
1) It's possible to run out of Dispatch Missions (offline), which leaves you the only option of doing the online ones. (Why would anyone bother with Online Dispatch Missions otherwise? They limited them for a reason,... very shady).
2) The online ones take forever (relative to offline ones), and you can expedite this by paying real-life money.
3) Connecting the game online makes the Combat Deployment menu hang for a long time -- basically freezes your game, probably due to server stress or whatever. I had to kill the application on my PS4 and restart it. All I know is that I don't like it, and I'm not returning online again until I beat the game.
If there is an ugly side to MGSV: TPP, the microtransactions are it.