You're familiar with the ease and flexibility of paying online, why not incorporate it into your practice? Offering a payment option that your clients use on a daily basis and allowing them to safely store their information will prompt them to pay you faster.
Not only are online payments a great experience for your clients, but you'll gain a new high-level insight into your law firm's financial health that can help you grow your business by allowing you to make more informed decisions.
It's a win-win.