Great question and thank you for your interesting in helping. Authentication via Reddit OAuth does not give “access” to the account. Reddit will send only your username and the list of subreddits you have subscribed to. I’ve set it up this way to help build out the list of subreddits.
In any case, you are right that other authentication methods are needed. I’ll change the setup soon to allow “traditional” sign-up, and I can also add other signup methods.