WideString is generally the only string type used to bind to Autocad and MSOffice (Win,Mac) scripting languages .....
...which is obviously a significant consideration. But my understanding is that the correct doctrine is that since the base language is Pascal, you're safer using Pascal-style strings and only converting to a PChar when calling an API or library that requires it.
I admit to being no great lover of this UTF-8 stuff, but there's really two issues here: Pascal vs C-type strings (AnsiString, String, WideString), and character representation (UTF-8 vs a fixed-width Unicode encoding).
MarkMLl