What does this add, really? It’s not automation (I can automate a couple of clicks in Proxmox), it’s not resource management (Proxmox handles storage, etc.). Is it developer identity? Because that’s the only thing I’d need a (relatively simple) script to deploy SSH keys to an environment.
Devcontainer spec is probably more developer centric than Proxmox templates
I would guess with your Proxmox setup in a team setup, you'd need to assign a hostname/ip for different developers, where with Lapdev you have a single point of access.
Lapdev can proxy http traffic to the workspace containers with authentication, which makes it easy to preview things with security.
Lap dev looks like a much simpler tool
But you could have gotten your answer by just checking my profile. But no. I just use Proxmox to manage all of my infra: https://taoofmac.com/space/blog/2023/12/17/2000
Don’t assume people have business motives for stating technical facts - and don’t downvote because they ask pointed questions. There are good reasons for pointed questions.