The JEs put 買い替え and 買い換え together without differentiating them. The kokugos only have the verb forms (買い替える, 買い換える) and don't distinguish between them I wouldn't suggest modifying the entry without more evidence than a single essay.

This article claims that the two terms carry different nuances,
and that 買い替え is the more general of the two.

https://www.alle-mo.jp/kaikae-kaikae/
　「買い替えは同じカテゴリのものを新しくすること」
　「買い換えは違うカテゴリのものと交換すること」
　「迷ったときは買い換えではなく買い替えを使っておけば問題ない」

Google N-gram Corpus Counts
1,189,151	 52.2%	買い替え
1,086,533	 47.7%	買い換え
    2,014	  0.1%	かいかえ

Search results:
"買い替え" About 27,200,000 results
"買い換え" About 11,900,000 results

@@ -5 +5 @@
-<keb>買い換え</keb>
+<keb>買い替え</keb>
@@ -8 +8 @@
-<keb>買い替え</keb>
+<keb>買い換え</keb>

Entry created