This article is based on my keynote speech presented at the 2018 Journal of International Accounting Research Conference held at Ca' Foscari University of Venice, Italy. The worldwide adoption of International Financial Reporting Standards in 2005 represents a “quasi-experimental” shock for thousands of companies around the world. This “Big Bang” event provided accounting researchers with an opportunity to gain insights into the fundamental qualitative characteristics of accounting that users find valuable. This research identifies several qualitative characteristics that help explain “why accounting matters,” including: (1) reliability, as captured by strong legal institutions, (2) accruals, (3) increased disclosure, (4) greater comparability, and (5) the use of historical costs (at least for contracting purposes). Notably, the overarching characteristic, which is necessary for all of the other characteristics to matter, is strong legal institutions.