But what if there were floating position(s), and there is connection problem between your terminal and the server and takes minutes or hours to resolve it, or your PC/VPS got hardware problem and need to be turned off for a while.
The EA wouldn't know what happens in the market and unable to do anything(it won't even be running if the PC/VPS need to be turned off)

If there is spike or sudden reversal during this offline time which goes against you, Stop Loss will protect you from getting too much loss (for some people trading w/ high risk will protect them from getting margin calls)

For example, a few months ago i was waiting for my position to get 150pips profit( i already got 143pips, just need alittle "push") so i keep waiting and watching the chart,
but then i need to go to the toilet, and i go for about 10 minutes,
At the time i returned the price was dropping 300pips, and i was like "WTF i got big minus O_o, i should have use SL"

And it takes days for me to be able to close that position with less than 100pips loss
(there is no chance that the price will goes up and gives me green pips that week, and i usually don't like keeping my position open for more than 24hours)

stay away from the toilet!!!!