  An intelligent reflecting surface (IRS) is an array of discrete elements with
configurable scattering properties. It has the capability to beamform arriving
radio waves to an intended receiver, making it an attractive candidate
technology for fifth-generation (5G) communications. A recent study debunked
the notion that IRSs can replace relays because a large number of IRS elements
is required even to approach the performance of simple single-antenna
decode-and-forward (DF) relays. The study introduced 4G channel models into a
theoretical framework to obtain simulation results, based on which comparisons
between the two schemes were carried out. In this paper, we consider 5G channel
models, reflect on the revised results, and argue that IRSs and DF relays can
complement each other's strengths and can both have a place in 5G and beyond 5G
architectures.
