I understand your point here. It is very easy to disable accounts, just while learning TOAD. So it is only when a user has got a good understanding of SQLs and Oracle bits and pieces that he should go ahead with using TOAD.
Everything that TOAD does or shows you is just SQL being executed. It's lovely when you don't want to keep typing all of the time. Even with it's problems (lots of AV's per day, inaccurate dataset representation etc) I still believe it is at this moment the best Oracle tool available. Even with that, I still complain about it and recommend it :-)
It is also usefull for learning, there is (somewhere on one of it's menus) a "spool SQL" option so that you can see what it's doing. I have learnt a fair bit from looking at that and following what it's doing.
It is a great tool (I will still complain about it) but it is also a dangerous tool. It can also be very slow, just look in SYS.V$SQLAREA for all TOAD initiated queries to see it can be quite heavy on a busy Oracle database.