Spent $260 on a biscuit joiner for a bookshelf build and used it exactly twice

Bought a DeWalt biscuit joiner about 8 months ago because a guy on YouTube said you can't build a decent bookshelf without one. $260 plus another $40 in biscuits. Used it on two joints, messed up both because I didn't account for the blade offset, and went back to pocket screws and glue like I'd been doing for 12 years. The shelf is still square two years later. So here's my debate for the group: is a biscuit joiner actually worth owning for a one man shop, or is it one of those tools that only earns its keep if you're doing production work and cutting 50 joints a day? I've talked to two guys who swear by theirs and one old timer in Spokane who told me he sold his after a month and never missed it. I want to hear both sides before I either sell mine on marketplace or give it another shot. What did you actually use yours for that made it worth the money?