Advantages of creating RTF log files

For most of the application,we need to create log files to keep track of the user interface....earlier we used to .txt files for it....now we can use rtf files because it has more features than a ordinary .txt files....eg..whenever we encounter an error in our application...mostly we will refer the corresponding log file to track the error.....in that case to easily track the problem,it would be good if the error message is given in bold or in some other color for fast tracking...but in normal .txt files this formating cannot be done...so we can use rtf files to add those features to our log file....