Thank you for your suggestion!
Actually, quite a few of us Japanese people also write 「わかります」, so I won’t say this is incorrect. But since you get to see the hiragana in a different column anyway, maybe we can write it in Kanji here so that you can learn the kanji as well. Thank you for your suggestion!
What you have to be careful is that わかります can be written in different kanjis (分かります、解ります、判ります） and they mean slightly different things. For example,
分かります：駅への行き方が分かりません。：I don’t understand (close to “know”) how you get to the station.
解ります：このマシンの仕組みが解りません：I don’t understand how this machine works.
But it’s also true that fewer and fewer people are being strict about these differences nowadays.
Thank you for your input!