Are there benefits to use XeTeX or LuaTeX if one is to write documents mainly in English?

Question

My first exposure to LaTeX was back in 2014 from this tutorial and I settled with the pdfTeX engine because it was the only thing I knew and I was a total novice.
Lately, I started reading Tobias Oetiker's The Not So Short Introduction To LaTeX from CTAN and realized that I have been unaware of the existence of so many things such as the polyglossia package as well as XeTeX and LuaTeX.

I am very curious about these two new engines and started browsing this site to know more. From my understanding, these two support natively UTF-8 encodings but I usually typeset documents in English and in Malagasy. Thus, ASCII characters are more than enough for my everyday use. Apart from the everyday use, I also plan to use LaTeX to typeset my thesis (in English) for my final year.

All that context being said, I am curious to know if there should be a reason for me to start using either of these two engines or wether pdfTeX is amply sufficient for my indented use and if I should just stick with it.

Answer 1

Some of the advantages include:

• Being able to use unicode-math and copy, paste and search for math symbols
• Not being limited to sixteen math alphabets
• Not having to juggle 8-bit, or even 7-bit, text encodings
• Being able to type symbols into your source code and have them work without a lot of set-up to declare them active
• You can use any font on your machine without a complicated conversion to Type 1 format
• Certain LaTeX3 interfaces only function properly if the engine supports Unicode natively
• Even in English, you will often use non-ASCII characters, such as opening and curling quotes, dashes, ligatures and the occasional accent. You could theoretically make these copyable and searchable in PDFLaTeX with the mmap or cmap package. But I never see anyone do that, and I’ve frequently seen papers with typos like “di cult” because someone used a font with no ffi ligature.
• You can use the extensions of the engines, such as XDV output (useful for document conversion) and Lua scripting.

A major application of this is accessibility. If a reader can identify a symbol, it can pronounce it for a visually-impaired user, as well as being able to convert it to another format.

Answer 2

To answer to how get rid the U+200B character using pdflatex:

The 'ZERO WIDTH SPACE' (U+200B) as the name suggest, is a space without space, but you can note that the character is there because you need press the cursor key twice to pass to the next/previous character.

This causes problems because pdflatex does not know what to do with that, unlike xelatex and lualatex.

To clean it you can use any text tool able to and search and replace this character in all the docuemnt. Only as example, Texworks or Gummi in Linux allow type the character with:

Ctrl+Shift+u200BEnter

Then, you can copy and paste in the search tool and replace with nothing some other character to see where it was. If you have problem with this, other solution is tell to pdflatex what to do. Consider this example:

\documentclass{article}
\usepackage{xcolor}
\DeclareUnicodeCharacter{200B}{ \colorbox{yellow}{\sffamily\bfseries u+200B}
\typeout{}\typeout{WARNING: Bad character U+200B in the line \the\inputlineno}\typeout{}}
\begin{document}
a​b

cd

e​f

asasa
\end{document}

This will show these warnings in the log file:

WARNING: Bad character U+200B in the line 6

WARNING: Bad character U+200B in the line 10

And the PDF will show also where they are:

But probably is better leave it as it really is, and forget it:

\DeclareUnicodeCharacter{200B}{\hspace{0pt}} 

Answer 3

This is an already closed topic, but I want to add a practical example. Several years ago, I wanted to use LaTeX to write a CV through modercv class. But added some hck to improve the machine readibility of the documents by those Applicant Tracking Systems softwares, that strip all your formatting, and keeps the text. The ligatures from LaTeX sometimes kills this conversion. And I was using some icons on my CV that were also creating issues. Switching from pdflatex to lualatex solved many of these issues. Most of the stuff is documented on this old post How to improve machine-readability of a CV created in LaTeX with moderncv?