Using hit die in 5e for new things

I am working on a gamma world conversion from 4th edition (1980s) gamma world to 5th edition D&D. While working on mutations I started using the expenditure of hit dice during short and long rest to represent some of the plant mutations that required "Growing" things like fruit and vines etc. Things that use to regrow over a period of time. I wanted to track less stuff so made it a Expend two hit die (Cumulative) to grow back a fruit during a long rest.





So that got me thinking of expending Hit dice as a means of powering abilities or even magic items. Representing putting personal energy into something to power it.



so I was wandering what the community thought.

Using hit die in 5e for new things