Kudos; this is likely a very useful tool! So useful (and potentially lucrative) that AWS/GCP would likely take over this functionality eventually -- either by

Kudos; this is likely a very useful tool! So useful (and potentially lucrative) that AWS/GCP would likely take over this functionality eventually -- either by building on top of spot instances like you have, or underneath regular instances or re-use that capacity for some other managed service (thereby reducing the price differential). How do you plan to protect yourselves against that?