It is harmful and I have seen it many times. People are often selected on their frontend portfolio but they did 'a bit of backend' as well and thus they are 'fullstack'.
The end result is systems that are completely lob sided; nice frontends in the latest tech with insecure, slow, badly created backends that crumble under load. But it doesn't matter because you can get better performance throwing money at it in a pretty simple straightforward way, while hiring other programmers, refactoring etc are very unsure endeavors(it could end up worse, deadlines aren't made etc).
I have said it here many times before here; a lot of funded startups (especially) simply prefer to burn investor money rather than do things properly. I see aws/gcp bills of 20-100k per month that can be below 10k with a few weeks (sometimes even days) of effort from someone who knows what they are doing, but nope, not happening. Automatically resolvable mistakes like having no (!!) indexes in a mysql database and so running $8k/month db bills to keep it performant (multiple times often) is becoming a little be too normal for my taste.
The end result is systems that are completely lob sided; nice frontends in the latest tech with insecure, slow, badly created backends that crumble under load. But it doesn't matter because you can get better performance throwing money at it in a pretty simple straightforward way, while hiring other programmers, refactoring etc are very unsure endeavors(it could end up worse, deadlines aren't made etc).
I have said it here many times before here; a lot of funded startups (especially) simply prefer to burn investor money rather than do things properly. I see aws/gcp bills of 20-100k per month that can be below 10k with a few weeks (sometimes even days) of effort from someone who knows what they are doing, but nope, not happening. Automatically resolvable mistakes like having no (!!) indexes in a mysql database and so running $8k/month db bills to keep it performant (multiple times often) is becoming a little be too normal for my taste.