DACs and ADCs are frequently used for digital communication - for anything RF/wireless they are a key part! Some high-speed SerDes receiver designs are even digitising using fast ADCs and DSP techniques internally now to do things like equalisation in the digital domain too, which is interesting (e.g. [1], [2]). Previously, slower (like 25Gbps and less) SerDes have tended to be purely analogue circuits until near the very end.
1. https://www.youtube.com/watch?v=OY2Dn4EDPiA
2. https://ieeexplore.ieee.org/document/8778136
