Mostly it’s messy and looks like hammered dog poop. It’s also unnecessary it you’re going long grain to long grain with moderate clamping- pva is all you need.

For weird matériels or less than ideal situations/no clamps I prefer it or epoxy over wood glue. Wood glue loses most of its strength if there’s any gap or finish on the joint.

Also it usually won’t penetrate into endgrain to get a good bond- lots of YouTube videos on guys like Mathias Wendell and others strength testing different joints and glue joints! I recommend many diy’er to watch some so they have a comparative understanding of different basic construction methods - then you can pick appropriately

And ideally avoid endgrain or anything with finish on it- you’re not gonna get wood glue to stick to something painted, clear coated, waxed or pre stained. I can’t tell from op’s description but if it’s gluing new pieces to prefinished, use a construction adhesive or nail in cleats to support the shelf