Membrr does not store any credit card data locally, so it is not a security risk in this point of view.
Usage scenarios include custom access plans to some website sections, running a local pay-to-download section, running a premium section, etc..
Here are some key features of "Membrr":
· SSL support
· Manage multiple subscription plans
· Customize the duration for every subscription
· Recurring billing
· Support for multiple payment gateways (PayPal, Authorize.net, SagePay, Wirecard, PacNet, VersaPay, eWay, FreshBooks, 2Checkout, PayLeap, PayWay, Stripe, Quantum Gateway, etc.)
· Support for offline payment methods (cheques, money erders, etc.)
· Send automatic email notifications
· Payments section integrates with the users management section
· Members themselves can manage subscriptions
· Invoice generation
· ExpressionEngine 1.6 or higher