In 3DIC and HPC packaging, achieving both high-precision assembly and reliability demands a careful balance of material properties. Glass offers low CTE, high flatness, and low dielectric loss, yet faces trade-offs such as TGV reliability and stress management. This study argues that, without clearly defining the necessity of glass, application development lacks momentum. By analyzing these inherent contradictions, we discuss how to interpret and manage the trade-offs between material properties and system reliability, providing insights toward the future direction of glass utilization in advanced packaging.