Use of \null versus \hbox{} in a table made with the longtable package

Question

In this answer, \null is said to be equivalent to \hbox{} and is therefore never needed. The same advice is more or less given here as it's not a user-level macro, which I take to be the same as "don't use it after \begin{document}".

I'm compiling a special calendar (using longtable), where some cells need to be empty. There's simply no entry for them. The original code which I'm borrowing uses \null for the blanks, but I'm wondering if that should be replaced by \hbox{} or if it would instead have any deleterious effects.

Here's an MWE stripped down to the bare bones. I don't know slash don't understand what's going on under the hood so to speak, but at least a Ctrl + F search-and-replace would be a trivial fix. Thanks for your insights.

\documentclass[11pt]{article}
\usepackage{longtable}
\usepackage{multirow,makecell}
\begin{document}
\setlength\LTleft{0pt}
\setlength\LTright{0pt}
\setlength{\tabcolsep}{5pt}
\renewcommand{\arraystretch}{1.4}
\fontsize{8}{9}\selectfont
\begin{longtable}{>{\centering}p{0.025\textwidth}|>{\raggedright}p{0.040\textwidth}|>{\raggedleft}p{0.025\textwidth}|>{\raggedright\arraybackslash}p{0.85\textwidth}}
text & text & text & text \ %% this looks ugly, it's fine for sample purposes.
\null & \null & \null & text \ %% this generates empty space as needed.
\hbox{} & \hbox{} & \hbox{} & text %% it appears the same as the above line.
\end{longtable}
\normalsize
\end{document}

Answer 1

Since \null is the same as \hbox{}, there can be no difference.

But there's no difference also if you type in nothing at all, which is actually the preferred way.

\documentclass[11pt]{article}
\usepackage{longtable,array}
\begin{document}
\begingroup
\setlength\LTleft{0pt}
\setlength\LTright{0pt plus 1fil}
\setlength{\tabcolsep}{5pt}
\renewcommand{\arraystretch}{1.4}
\fontsize{8}{9}\selectfont
\begin{longtable}{
  >{\centering}p{0.025\textwidth}|
  >{\raggedright}p{0.040\textwidth}|
  >{\raggedleft}p{0.025\textwidth}|
  >{\raggedright\arraybackslash}p{0.7\textwidth}
}
T & T & T & T \ %% this looks ugly, it's fine for sample purposes.
\null & \null & \null & T \ %% this generates empty space as needed.
\hbox{} & \hbox{} & \hbox{} & T \ %% it appears the same as the above line.
T & T & T & T \ %% this looks ugly, it's fine for sample purposes.
 &  &  & T \ %% this generates empty space as needed.
 &  &  & T \%% it appears the same as the above line.
 &  &  & \ %% this generates empty space as needed.
 &  &  & T \%% it appears the same as the above line.
\end{longtable}
\endgroup
\end{document}