Datomic's 'time travel' is an audit feature, not something for your application/business logic to depend on. Performance reasons make it impractical, unless you only have like 10 users and very little data.
The first feature on benefits (and the only reason I've ever heard Datomic brought up and/or considered it myself for production workflows) is using that stuff in application workflows: https://docs.datomic.com/pro/time/filters.html#history
Could be you're saying it in fact doesn't work well performance-wise, that'd (surprise me but) certainly explain why it's not more popular -- but I think it's clear it wants you to use this as an application feature.
Datomic is great but as another commenter said, is good for "small-ish backoffice systems that never has to be web scale". You almost probably can rely on querying history for internal applications. I think their primary market was for companies to use it internally but they never made this clear.
And 9996 of them are used for stuff like the internal HR DB or other minor projects.
He lucked out when a unicorn went all in on it. Word around Cognitect was, Datomic was barely breaking even.