"[based on 1 Cor. 12.7] As we shall see, some wish to rule out the legitimacy of any private use of tongues on the basis of this and similar texts: What possible benefit for the entire community is there, they ask, in such private tongues-speaking? Clearly there is no direct benefit: no one but God is hearing what is being said. But Paul was granted extraordinary visions and revelations that were designed only for his immediate benefit (2 Cor. 12:1-10); yet surely the church received indirect profit insofar as those visions and revelations, not to mention the ensuing thorn in his flesh, better equipped him for proclamation and ministry. In the same way, it is hard to see how verse 7 of this chapter renders illegitimate a private use of tongues if the result is a better person, a more spiritually minded Christian: the church may thereby receive indirect benefit. The verse rules out using any charisma for personal aggrandizement or merely for self-satisfiaction; it does not rule out all benefit for the individual (just as marriage, one of the charismata according to 1 Cor. 7:7 may benefit the individual), providing that the resulting matrix is for the common good. The context demands no more."
I think the Carsmeister has nailed this one!