Mat 9:30 And their eyes were opened; and Jesus straitly charged them, saying, See that no man know it.
We often read Jesus' admonitions to those He healed. "Don't tell anybody."
I believe the main reason is that the danger in doing so would produce more misery in their lives than they experienced by their diseases. The religious crowd hounded and persecuted those whom Jesus touched.
By testifying, they were inviting scrutiny and possibly banishment.
But, as it should be with us, they just can't hold the good news in, "Jesus saves!"
We don't face much persecution and therefore, the proclamation of the Lordship of Jesus should hold no fear.
Go, tell the world of the love of Jesus.