Duane, I'll give you that USATF maintaining the course certification program is a benefit. However, I seriously doubt that a measurer has ever been denied a measuring job based on USATF membership.
As far as "making money" from measuring goes, I don't look at measuring as an income stream, more like a hobby that pays a little. The hourly rate realized by measurers may actually qualify as a disadvantage of USATF maintaining the certification program. I don't think the majority of measurers do it solely for the income. Maybe you could say that tangible benefit of USATF maintaining the certification program is that it provides me a hobby that costs way less than golf. All this is reaching and would never alone convince someone to join USATF.