When we need to visualize complex number, we can use polar plot.
E.g., in Octave
handle1=plot(real(s11), imag(s11), 'Color',[1.0,0,0]);
Simply using real part of s11 for x coordinates, and imaginary part for y coordinates.
This graph also can be called a Smith chart, we can add constant resistance circles, stability circles, etc.
There is no need to eliminate Smith chart, as well as polar coordinate system

Smith chart is used in a lot of books and recognized by many people. It may help to remember some concepts. E.g., see here is Smith chart visualization of patch antenna inset length tuning compared to patch dimensions tuning:
https://youtu.be/v8uxhbu36Ug?si=GXQMQTdlT_ddQQCy&t=32When we tune inset length, we jump between resistance circles (S11 curve radius changes)
And when we change patch dimensions, we tune resonant frequency (point moves along S11 curve)
Maybe seller meant that Smith charts are no longer used in paper form to design matching circuits. A lot of CAD programs provide polar plots and call them Smith charts. Some hatred toward Smith charts is caused by unnecessary complication: drawing all those circles at different offsets and pushing into student heads. Maybe teachers should have used simple polar plots without all those circles and terminology first. So, if Seller doesn't like Smith charts, it's not his fault!
Smith chart would be especially handy if I design series-feedback oscillator, tunable impedance block (measuring S22 for FET while tuning Vgs bias).