Personal spending happens on business accounts in almost every small business. Marking it as personal keeps it out of your expense figures rather than filed into the nearest plausible category.
Why it matters more than it looks
An owner's grocery shop sitting in "office supplies" does three things: it overstates costs, it understates profit, and it makes the expense ratio for that category meaningless.
Do it across a year and the business looks less profitable than it is, which affects every decision built on those figures — pricing, hiring, whether you can afford anything.
It also makes the year end harder, because somebody has to separate it later with less context than you have today.
Where to do it
On the transaction, in Transactions or during reconciliation.
Marking it is not the same as taking money out
A personal transaction on a business account is effectively an owner draw. If it is a regular occurrence rather than an occasional slip, it is worth recording properly as owner pay so the amount is visible.
The habit that removes the problem
Separate cards. It is the single change that eliminates this category of work, and most owners get to it eventually — usually after a year end that took longer than it should have.