Physical keys and coded entry are a bollocks and any employer in their right mind should be looking to ditch them ASAP. In my last place I had to help with gaining ISO270001 compliance and part of that was controlling physical access to the areas that might contain sensitive data. Not that bikes are sensitive data, but restricting physical access is the same regardless.
Keys - these get lost and for proper accountability, records need to/should be kept as to who has them. This is often why it is expensive if you lose one as the cost is an incentive to keep hold of the bugger. It is also not very secure, as people go an get other copies cut for their mates. Technically, if one is lost or someone leaves without handing theirs in, you should change the locks and issue new keys to everyone who is supposed to have one.
Coded locks - Even worse, as the privilieged few just need to tell their mate(s) the code. Or they will write the code on a slip of paper that they will undoubtedly drop just beside the lock when fumbling through their pockets for it. Depending on the device, they can be easily 'picked'. And if anyone leaves, you need to change the code, much to the annoyance of everyone else. Also, they break, all the fucking time, especially if exposed to the elements.
Swipe card access is by far the best solution, especially if it is being rolled out through the rest of the building. It uses existing (barring maybe one or two additional locks/readers) infrastructure, it can be tracked to individual users and access times which improves accountability and security (something goes missing? check CCTV and who accessed the area at what time). You can also see who uses it and when so if someone has access but doesn't use it, you can assume they don't need it and given the limited space, restrict one and allow another through the central management portal. Way easier than getting new keys cut, asking for old ones back, changing codes, thinking of a secure way to distribute the code yada yada yada.
TL;DR - swipe cards - will be easier and cheaper to manage and more secure.