Well, I’ve and see my ‘OP5T’ and installing /e/OS ‘Q’ works with TWRP as well as eRecovery.
Two advantages of eRecovery I can see for ‘normal’ users:
1] straightforward /e/ OS from installation point of /e/ documentation ‘Installing /e/ from recovery’.
2] OTA update processing in the background (without TWRP messages becoming visible as with TWRP) as well as Update recovery - Update the built-in eRecovery with system updates.