While I agree that Scripture isn't *necessary* to accept Christ, it doesn't follow that it is irrelevant. You might be able to kill a deer with a heavy rock. That means a rifle is unnecessary. But I don't think you'd argue that a rifle is irrelevant to such action - it is a different means to the same end.
Besides, the OT prophesy is not all that clear-cut, or else the Jews in general would have recognized Christ purely on the basis of their scriptures.
One can argue that perhaps God didn't want them to, so what good is scripture is there is no God-given faith?
Absolutely it is not clear-cut. And faith is necessary to fully comprehend Scripture. But God can use Scripture to build faith - how many stories are there of people changing in a hotel room after reading Gideon's Bible?
Agreed, but that makes the scriptures just one of many, indeed a limitless number of means available to the same end. Yet, most Protestants profess sola scriptura as the only way.
But God can use Scripture to build faith - how many stories are there of people changing in a hotel room after reading Gideon's Bible?
It's not what God can or cannot do, but what is necessary for faith to appear. Frankly it sounds a bit naive to say that God chooses to "download" faith to people like Paul, Job, Lot, Abraham or Noah, while subjecting others to life-long studies of scriptures. God is not partial or changing.
This thing about different means towards the same end sounds a bit like a rationalization to me although on the surface it "makes sense" in a human box. With God, rocks and rifles are not an issue. By definition, God is perfect and perfection does not come in different varieties.