Disclaimer: I suspect "data centers in space" is just blatant market manipulation by Elon, exactly the same as he'd done dozens of times before with self-driving, etc.

Having said that... it might justify the valuation if every other data centre build-out gets blocked by insufficient power supply.

Might.

Bear in mind that you could take the solar panels that you would have launched into orbit, use the launch costs to purchase additional solar panels, batteries, and some additional land, and build a data center plus solar farm plus grid scale battery bank on the ground for probably (almost certainly) less than the combined launch costs.

I think the only way compute in space works out financially is if there's so much bulk data already up there that downlink bandwidth becomes a serious bottleneck.