Reflecting on your question, the difference between backtested results and trading realtime includes all the natty little nuances of living in an imperfect world as an imperfect person, some of which are, but not limited to:
lost connectivity
passing the wrong trading parameters
bad feed
temp computer problems
news/rumors
not getting filled at the price the system thinks it got filled at
tweaking your system (changes everything)
Your nerves and quality of life
Can it work nonetheless? Sure, why not? May it not work nonetheless? Certainly.