Deoplete supports Vim 8.2 +python3 +timers 
The autocomplete layer's logic does not enable Deoplete with Vim 8.2 +python3 +timers, only with nvim. The documentation also reflects this.

Tested on a Vim 8.2.1895 build with +python3/dyn +timers -lua, asyncomplete is automatically chosen instead.

See also #4156