It's a traditional approach in image editors (other notable examples include Photoshop, CorelDraw, GIMP, Krita, Pixia, and as remarked in other comments AzPaint

It's a traditional approach in image editors (other notable examples include Photoshop, CorelDraw, GIMP, Krita, Pixia, and as remarked in other comments AzPainter) but not in audio editors. I blame the traditional prevalence of highly self-contained plugins and little scripts (for example, Audacity has Nyquist scripts) that entail generic host applications that only really care about the subset of features that cannot be delegated to plugins (for example, Audacity has the waveform view).