I will agree that if one uses fields seldom searched on the method of pulling those in under Outlook is tedious. One nice thing, though, is once you've formulated a search it gets saved in Recent Searches.
It's interesting that in my step-by-step instructions for doing an Outlook Advanced search for screen reader users I state the following, which I stand by: Advanced Tab – so seldom used I will not discuss it here. I used Outlook in several different professional settings over the course of decades and never did a search where I had to call on the Advanced Tab.
I have absolutely no idea regarding comparative search speed. Some of that's likely dependent on what gets indexed, which Outlook lets you configure, too.
Like all software each has pluses and minuses. In the case of e-mail clients certain features are passionately beloved by some, while being considered a big "meh" by others. The identities feature of OE seems to be one of those. I never knew of anyone who used it, but it's certainly beloved on the blind and low vision technology groups on which I participate.
There is no right or wrong here; it's all a matter of personal preference.
Brian - Windows 10 Home, 64-Bit, Version 1803, Build 17134
The psychology of adultery has been falsified by conventional morals, which assume, in monogamous countries, that attraction to one person cannot co-exist with a serious affection for another. Everybody knows that this is untrue. . .
~ Bertrand Russell