Short answer

They accept different cards, and everything else follows from that. A full-size SD socket takes the 24 × 32 mm card on 9 contacts; a Micro SD socket takes the 11 × 15 mm card on 8 contacts. Both handle the same SD protocol, so the choice is mechanical and spatial, not electrical.

Compared where it counts

• Footprint — a Micro SD socket occupies roughly a quarter of the board area of a full-size one.
• Height — low-profile Micro SD sockets fit phones, drones and modules where a full-size slot cannot.
• Write-protect — the physical tab exists only on the full-size card, hence only on its socket.
• Insertion cycles — both families are rated for 10,000 cycles in quality designs; field card swaps favor the more robust full-size mechanism.

How to choose

If the card is installed once at assembly or updated by firmware, Micro SD saves space. If the card is swapped by people — cameras, industrial loggers, test gear — a full-size or push-pull SD socket is easier to handle. MOARCONN produces both families across 15 series and 163 part numbers, so the trade-off can be made on design need rather than supplier range.