IIRC technically dos4gw (and similar) doesn't need himem.sys or emm386.exe since it can access the memory directly. Of course if you don't load himem.sys and emm386.exe then what are you going to do with your other TSR/drivers unless you boot with a clean config.
Also even though they may not technically be required it depends on how the software was programed since sometimes the program will check for himem.sys or emm386 and fail to load if they aren't present.
Finally DOS(not 9x) himem.sys has a 64mb limitation and emm386 (which requires himem.sys) has a 32mb one (unless you add some switch).
No DOS game needs more than 64mb anyway so not really an issue. (Not counting any DOS ports that are still being developed 😉 )
I usually tried to make a one size fits all config with memory to load tsr/drivers in HMA, extended, and expanded memory, etc.
If I ran into a situation where there was a compatibility issue then I had a bare config with only the essentials.