In the March hearing on a voluntary ACS, the three external witnesses -- from the American Enterprise Institute, National Association of Realtors, and Greater Houston Partnership -- all spoke about how important ACS data were (and all agreed it should be mandatory). Subcommittee Chair Trey Gowdy (R-SC) and Full Committee Chair Darrell Issa (R-CA) also affirmed how important the ACS is.
Articles on the topic also discuss the strong support of groups like the U.S. Chamber of Commerce. See, for example, this Business Week article by Matthew Phillips, "Killing the American Community Survey Blinds Business."
An analogy I like to use when discussing the importance of economic statistical data is that of ship having to navigate a difficult strait (rocky outcroppings, sandbars, tricky currents/tides, ...) in rough weather and with other ships present. Complicating the picture is the need to cut the budget for the voyage. While there are many ways to trim the budget, I would contend that one does not want to cut a budget that would in any way undermine navigational data, whether it be geographic topography, weather, currents, or ship and iceberg locations. If anything, I’d want more reliable data.