In the current climate of design, fonts could reach across many platforms and places. Why would it be important for ones font to be accessible to everyone and in all formats?
As fonts come in an array of unique styles, each of which has its own visual meaning (to emphasize on the presentation of wording), appearance is not only important but also is its formatting. Formatting fonts allows their use to be available to anyone and everyone which is why several formats exist: namely PostScript (Type 1), TrueType, OpenType fonts. Looking at the first three font formats, each chronologically came after the other at a time when advancements in printing techniques and programming were evolving. PostScript, which is the oldest, was used in professional typesetting and desktop publishing applications.
Since Mac and Windows computers each had differences in how the font was built (consisting of two files: a screen font with bitmap info for viewing and a file with outline info for printing), a typical version of Postscript was not cross-platform compatible. Next, Apple developed TrueType which was later adapted by Microsoft. TrueType was able to fix the problem of having two separate files of screening and outlining information of a single font which made the format cross-platform compatible albeit its issues in scalability which rendered a font differently depending on the operating system (Mac or Windows).
Finally with OpenType, Microsoft and Apple jointly developed a format of making fonts where like before there would be a single file for outline and bitmap data for a font but with the added effect of having PostScript or TrueType data to enhance scaling and other features. In addition, OpenType introduced extended character sets and more advanced typographic controls and thus, this font format set the standard for cross platform use with the same rendering on both operating systems.
Simply put, looking at the evolution of font formatting, there was certainly an effort made to unify the programming language so that users can have the same access to fonts whether from a Mac or a Windows computer. I believe that the importance in having fonts reach many platforms and places is multifold. As already established with OpenType, since users of both operating systems could access the same fonts, the advantage here is that if users are working on a document using a particular font on one computer, then it is easy to work on the same document on another computer (under another operating system) using the same font, especially if such a user is using a flash drive or cloud to transfer their documents.
Even without OpenType, using PostScript has its benefits too. PostScript allows a user to consistently control text and layouts and will always show the same layout of text no matter what output is used. In that sense, users of either Mac or Windows computers can still use PostScript for those means but at current time, OpenType is being adopted by more publishing companies which will undermine PostScript use in the future. Ultimately, this signifies the importance of having fonts made available on many to all publishing formats to further cater to computer users, whether for home, personal or business use where each would require certain font use (e.g. Arial, Calibri) on certain documents (i.e. PDFs, word documents).