What term of safe are we referring to? Anyone can secure their holdings without switching to XMR. If you’re after the privacy it’s common choosing XMR meanwhile bitcoin for long run is profitable, XMR is more private and stable meaning it can be use as fiat in most location and it promotes anonymity unlike bitcoin blockchain. If bitcoin doesn’t support same features as XMR although your friend is right but it doesn’t make bitcoin unsafe, I disagree and if you feel like converting your coins it all depends on your goal.