Praying in tongues has benefits
Just as Paul was not ignorant of the power of prayer and speaking in tongues, neither were the early Christians. The early Christians understood that they could not neglect prayer:
But we will give ourselves continually to prayer and the ministry of the word.
God is always is speaking but we cannot seem to discern his voice. The chief reason for not hearing him is due to all the other voices in the world clamoring for your attention.