I mean, there’s still the possibility of learning WK’s vocab or doing KW later on… but why would you do that? Sure, getting extra free time for other things might be useful… but you’d lose momentum of something that you’ll eventually have to learn.
If you can’t find time for WK + KW, either improve your efficiency (my 3 times/day routine) or reduce your speed. The cool thing about learning Kanji on WK is that you easily reach a point where kanji is your best skill and you simply don’t need it much higher to practice your other skills.