Toy model showing the effect on distance determination of unresolved binaries. The gray dashed line shows the reference case, made of only single stars. The blue line shows the effect on distance determination for binaries and the red line highlights the effect on asteroseismic binaries. The black dotted line indicates the expected relative distance difference in the case of a twin, i.e., a binary where L₁ = L₂, ignoring the effect of measurement errors.