Having used HAProxy for 15 years commercially, I absolutely agree with this. There are lots of complex features of HAProxy that only a dedicated proxy can provide. The acls, deep packet inspection and stick tables are a few.
Whilst it doesn’t directly “serve” PHP or Python - it’s a load balancer so can just have regular Apache or nginx backends serving content which is arguably its main use case. For homelab this doesn’t always make sense but I would pick nginx for high traffic commercial environments.