To convert to discs or not convert? That is the question!

I assume the "brakes guru" is referring to the '72 and earlier Kelsey Hayes disc brakes, which have historically been difficult and expensive to find parts for, but even finding parts for these brakes is no longer difficult. And certainly '73 and up disk brake parts are widely available, as are aftermarket kits.

I think your "guru" might be misinformed, or using dating information.