I've been a BSPWM user for about 5 years now.
It's very comfy. The client is close to the shell, and you can have both automatic and manual tiling modes. When there is some feature you like that the author did not account for, you can query the state of the world in json and make decisions based on that.
A comment here mentions herbstluftwm, which came before BSPWM and I would even call a sister WM -- Baskerville even announced BSPWM on the Herbstluftwm mailing list when it was initially released[2]. I would say BSPWM has less to think about than in the other window manager (everything is a node vs climbing frames with nested layouts). It can be thought of as a kit for building what you want, even. For instance, I use a tag-based workflow[3], where I toggle the hidden flag of nodes, and keep only one desktop.
WRT the windows being kept as nodes in a binary tree, this is useful because you can then climb the tree and perform balances and rotations within a subselection of the whole thing. You can also use the tree datastructure to enforce layout, like here[1], a DWM-like stacking layout.
With monocle mode, you can add fake padding for fullscreen windows, allowing you to have comfy fullscreen stuff that still accounts for a panel presence. With an external rules script, you can make decisions about what to do with windows as they appear, allowing dynamic layouts and decision making.
I'm sure at the end of the day, you can get what you need with any window manager if you drill far enough (year of the linux desktop is here, if you are willing to read the source). BSPWM has been a nice base for flexible workflow types for me. I will also share screenshots I've taken over the years here: https://notes.neeasade.net/rice.html (all bspwm past mid 2014).
[1] https://old.reddit.com/r/bspwm/comments/euq5r7/a_dwmlike_sta...
[2] https://herbstluftwm.org/archive/msg00052.html
[3] https://github.com/neeasade/dotfiles/blob/master/bin/bin/bta...