Disk I/OB+Trees have high branching factors (100–1000 children/node), meaning fewer disk reads per lookup. A BST node holds one key; a B+Tree page holds hundreds.
Range ScansB+Trees store all data in leaf nodes linked as a doubly-linked list — range queries simply scan leaves sequentially. BST range queries require recursive traversal.
Cache EfficiencyB+Tree pages align with OS page cache (4KB–16KB). BST nodes are heap-allocated and pointer-chased, causing cache misses on every level.
Guaranteed BalanceB-Trees self-balance on every insert/delete via splits and merges. BST can degenerate to O(n) without explicit rebalancing logic.