The advantages of using frits in ceramic glazes include:
Achieving the desired shape of objects
Serving as an intermediate material in glass manufacturing
Making mixtures insoluble, enhancing properties like viscosity and fluidity
Improving the safety of toxic metals like lead
Consistency and frequent usability
Lowering the melting temperature
Enhancing melt predictability
Ens... https://www.ipnr-endura.com/ceramic/frits-for-tiles