I want to know the proper way of installing TWRP because recently I spent quite a lot of time bricking/unbricking my phones after flashing the ROMs, so I don't want spend it again. While learning the TWRP features I figured out two different ways of installing the TWRP:

[![enter image description here][1]][1]

So far I found many useful articles explaining ramdisk way of TWRP installation<br>
https://www.xda-developers.com/how-to-install-twrp/<br>
also quite a lot of beutiful questions/answers posted here on Android SE<br>
https://android.stackexchange.com/questions/201481/install-twrp-to-only-one-slot-or-offline-boot-img-file-not-both/201506#201506<br>
https://android.stackexchange.com/questions/209673/why-cant-i-write-to-recovery-using-fastboot-on-a-b-device/209692#209692<br>
https://android.stackexchange.com/questions/211996/cant-flash-custom-twrp-recovery-image-on-motorola-moto-g7-power-phone/212005#212005

Having read all that, I have a general understanding that newer A/B devices have no separate recovery partition where TWRP can be installed, so instead recovery is put onto the `boot` partition in some `ramdisk` section, or this is how I understood. Practically that means that one need to have recovery `.zip` or `.img` file in hand, and *push* that file onto the device to be able to install it on ramdisk.
As opposed, with `Flash current TWRP` we don't need any files, we just make the currently booted TWRP persistent, and bootable on next and subsequent boots.

The question is: are those two options have equivalent result? If so why we have them both in TWRP menu? 

In my understanding flashing the current TWRP is simpler as it does not require any file copy. Am I missing something?


  [1]: https://i.sstatic.net/zpFnZ.png