Even if it appears to do what you want, but you don't actually read and understand the code, how do you know it doesn't do something else also? Maybe something you don't want?
Irrelevant in vibe coding. If it walks like a duck and quacks like a duck, you don't go looking for extra heads, eyes, fingers, tongues, or tails. You ship it then throw repl.it under the bus when it blows up.