That may be true in some cases.
I have decades of PDF files that I have created for customers and never outlined the fonts in case I needed to edit something for the customer in the future.
I just quickly checked a small number of those files and most of them will open in LB and fonts that weren’t outlined and the text is editable. I stopped at first one that didn’t. I was able to open the PDF file in Inkscape, save the file as a SVG and opened it in LB. The text was as expected LB.
Maybe this has something to do with the graphic design software that I used to create the PDF files?
I also just learned that those Inkscape converted PDF to SVG files that the font is correct and text is editable in LB. In Inkscape I also saved the same file as a PDF and it opened fine in LB only if the text is outlined.