I'd certainly love one of these for a home lab. That's for sure!
I can see the whole ROBO deployment scenario. Even in single/several use situations, like you mentioned... such as for specific critical high-performing services that won't outgrow it. Anywhere else, I'd feel stuck with it... what happens if you start to outgrow the resources? How scalable is it? That's what would determine it's worth for usage in place of regular 2u deployment servers.
Maybe I'm just not a blade type person.
It's really meant for contained scenarios where you know how big you will grow. For a normal SMB, the issue is growing into it, rather than outgrowing it.
Blades seem to make you give up a lot of flexibility. With an old fashioned server I can run them diskless today and add disks tomorrow if the way that I want to use them changes. But if I have a blade, I'm stuck.
Something to consider with a VRTX is that that is eight to sixteen Intel Xeon CPUs in a loaded chassis. That is a massive amount of compute power (with very little storage throughput.) So you have the CPU power to handle easily ~400 typical VMs. But the storage capacity and throughput of no more than an R510. Even an R720xd or R730xd has more drive capacity than the VRTX. So the ratio of IOPS and capacity to CPU is wildly different than with normal servers.