why do you need .csv?
It shouldn't make a slightest difference to import .txt to Excel
The problem is if the data is fairly large it can take some time.
Also different data sources separate the packets using different methods like commas, tas etc.
An example is if you syslog the McAfee DAM logs to the ESM and store in the ELM to then map it in Excel is not that easy due to the mix of characters used to separate the output.