Is it safe to use FFXIV Apps parser?

[Bardo]

They don't officially support the use of log parser, but they would never ban people for using them because we can already export the log files to local machine with official support.
All a parser does is read these in realtime and condense the output into something more useful.

If you turn off everyone else's damage and healing and just show your own in the combat log, then a log parser can be a great tool to practice with and help you to get better.
The way the combat log currently works, it shows you used an ability on one line then the damage on another line.
Depending on timing it might show you used ability x, then someone else used ability y, then your damage, then their damage.
A parser has no way to know that your damage is associated with your ability x so it just adds your damage to the other person's ability y.

In other words, because of the way the combat log works, parsers aren't very good tools to measure yourself against other players in a party.