with grep I see all the alternatives, Ctl+R just shows me one

Brilliant

Why not just use an alias?

Some would call the former command cat abuse.

In short, unless you want the contents of a file printed to stdout (or multiple files concatenated), the command can probably be written without cat, instead using the filename as an argument (grep pattern file) or IO redirection (cmd < file).

Stylistics and readability are another thing though.