The 100-LQFP package (14x14 mm) is a rework-friendly footprint — visible leads, no hidden balls, and a reasonable thermal mass that won't cook the board under a hot-air station.
Memory and peripheral headroom
256 KB Flash gives enough room for a TCP/IP stack, application logic, and a small file system; the 64 KB SRAM supports moderate packet buffering without external memory. The 46 GPIOs, along with the internal oscillator and brown-out/POR/WDT peripherals, reduce external BOM count — you can run a basic node with just the MCU, a magnetics jack, and a 2.5 V supply rail.
Supply voltage and design-in note
That's tighter than the usual 3.3 V MCU, so the regulator selection matters: a 2.5 V LDO with ±2% accuracy keeps you inside the window. The internal oscillator means you can skip an external crystal for non-timing-critical applications, but if you do use one, the oscillator type is internal, so no external resonator is required for basic clocking.