Question Regarding Layer 2 vs Layer 3 Switch

Hey,

We currently have an ASA 5506 doing all the routing at our locations + ACLs.

Im looking to deploy a managed switch just because we will be adding a lot more devices.

From my understanding Layer 2 operates via MAC addresses via ARP table and Layer 3 operates via IP and does routing.

Since our ASA 5506 acts as the DHCP/Routing/ACL control etc... should I just purchase a Layer 2 switch? Or should I spend the extra cash and get Layer 3 and use Layer 2 mode for future proofing?