These are contradictory. What you literally means is that it would not work. Betting generally is risky.
My bad for wording it wrongly because i've seen others go for unusual methods in making their predictions like asking their significant other, roulette, simulations through games, pets, etc. It starts well and sometimes finishes with a positive record because they don't bet as much.
You're not wrong, it's risky regardless and that's why we always try to remind ourselves and other gamblers to spend within our budget.