No kidding! I wish I had seen this post one day earlier. Ever since I set up my T8 about 9 months ago, I've been frustrated by only one thing: The difficulty I have sliding the glass doors, particularly if my hands have any bit of moisture on them and all the fingerprints that end up on the glass doors from my kids and me sliding the doors open and shut (I realize that, technically, those are two things, but they really stem from one item: no handles/finger pulls on the doors). In a bit of ironic timing, yesterday I added little 3M Command hooks (the clear ones) to the outside of the glass doors to use as pull handles. I wish I had seen the LLL Reptile Plastic Finger Pull before I added the hooks. The hooks are definitely functional, but they aren't the nicest looking things (however, they do make a convenient place to hang the keys for the lock).
To address the OP's question, I don't think a lock is critical if you have the sliding glass doors; however, as others have mentioned, the locks do have several advantages, including: (a) keeping out people (e.g., when my kids have friends over, we hide the keys for the lock); (b) ensuring that you slide the doors all the way closed and don't leave any small openings for your ball python to use as leverage (to squeeze through and slide open the glass doors); and (c) making your spouse/signficant other who might not be as fond of snakes as you are (relatively) comfortable with the T8 setup.![]()