Can I use Spanbox on my work computer? Is it fine for company use?

Technically it runs fine on a work machine, it's just a desktop app loading web apps you already use. Whether you're allowed to install it is your IT policy's call, not a Spanbox limitation. One point in its favour with IT: it's local-first with no cloud account, so your company's data isn't routed through a third-party server the way a bridge-based tool would, which is often an easier approval.