BarTender:

 

fe31nz:

 

Unless you botch your configuration in a way that causes frequent writes to the USB stick, there is not a problem.  It only gets written to when you change the configuration or upgrade the firmware, and the actual number of writes is very low.  Anything that writes frequently (logs for example) writes to RAMdisk, not the USB stick.

 

 

I love the optimism, there is plenty of examples where developers who are lazy still keep on writing useless log messages to permanent storage causing excessive wear on the storage so the life of its on all the time means you can have a significantly reduced lifetime of the device. 

https://hackaday.com/2021/02/11/tesla-recalls-cars-with-emmc-failures-calls-part-a-wear-item/

 

At the time the Edgerouters were designed, Ubiquiti had some pretty good software engineers.  They did not make any mistakes like that.  However, the documentation should have had a warning in it to tell the users not to do it and where the RAMdisk was mounted.  That did not happen and quite a few users initially did configs that killed the USB drive within just a few days.