Miriam inspired by the praise and worship of the children of Israel (which was led by Moses) inspired the women of Israel to worship, their worship I believe would have blessed the entire nation – not just the women who went out.  This account shows us the tremendous contagious effect of worshipping in spirit and truth (Joh 4:24)  – it cannot be contained.  Further, it also shows that a congregation can be lifted to new levels of appreciation of our great God and Father by one person following the lead of the Holy Spirit.