Once, I did heavy interview prep because I was bored with my job at the time, I got good at it, and landed another better job.
A year later my company deleted entire orgs of people, and I quickly realized that I was in bad shape when my third rejection rolled in.
Interviews are high pressure situations. Better to be used to the flow, coding, and conversation style (again, think "sales") than to be caught off guard, worrying about whether you've solved a Leetcode question fast enough to satisfy another human with their own grading quirks.
Oh, and that person is standing between you and a steady paycheck. That's the part I have to practice anyway, solving stupid university final problems when my livelihood is on the line.