I work in the field and often see conference listings. I don't know why your CfA aquaintaince would say something like that. Almost all places are in cities, or nearby locations, with universities that have robust astronomy research programs -- they're well-justified locations for meetings. That includes places like Venice, Canary Islands, and Paris. The American Astronomical Society meeting locations are certainly not sumptious locations, in fact, i sometimes hear grumblings about it.
As for the tangible benefits of astrophysics ... ancient astronomy created the foundation for modern calendars, spectroscopy and nuclear fusion work in early astronomy was fueled by astronomy research, developing early CCD technology for imaging which is now used in digital cameras, x-ray machines (medical and airport), image processing software for detecting breast cancer tumors, radio astronomy interferometry adapted for locating 911 cell phone calls, adaptive optics imaging techniques used for imagining retina that can lead to earlier detection of disease, and more....
The most tangible benefit of all: inspiring kids to do well in school so they can pursue careers as scientists.
We get amazing technological spin-offs because inspired curious minds want to study nature; astronomers and engineers have collaborated with great success to create the instruments for pursuing their research goals. Without that thirst for knowledge, there would not have been any motivation to create some of the technological spin-offs mentioned above.
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