Nah. First, actually being good at leet and knowing about hashing and such are not in opposition. In odd way, leet exercises makes lead to math parts of it.

And second, non leet devs are not some kind of safety panacea. The worst are people who don't care at all. Many have not heard of basics.

Third, if you actually decide that security is important and try to learn it, you will find resources are rare. There is very little of it targeted at developers. There is no shared knowledge base. There are no commonly known processes. Nothing like that.

So even if you care and try, you end up learning very little.