Or don't, as we have seen recently relying on addons to add missing functionalities may not be viable through time.

Thunderbird will soon add support for webextensions, who knows what will happen of the legacy extensions further than short term ?

And you can't move whole conversations, for example. That's a huge pain point for me.

It seems to be a totally different thing than the regular message list, and only some actions work in Conversation mode.