Aesthetic-Usability is one of the User Experience Laws to live by. This effect was initially studied in 1995 and focused on human-computer interaction. UX Researchers, Masaaki Korosu and Kaori Kashimura tested different User Interfaces for an ATM and asked the 252 participants to rate each design based on the following criteria:
1. Ease of Use
2. Aesthetic Appeal
Their conclusion: users are strongly influenced by the aesthetics of any given interface, even when they try to calculate the underlying functionality of the system.
By paying closer attention to the visual elements of your physical or digital product, you create a stronger connection with your target audience and sway them to feel at ease when the use your product or digital product. When we only focus on the user experience, and ignore the user interface - even when the UX is strong, you risk creating a disconnect with your target users.
A major issue when you shortcut your visual identity or the visual elements of a product/digital product is a lack of an emotional connection from your audience. Without that connection, users tend to be less forgiving of usability issues. When you are creating the UI of a product or digital product, rely on the user research provided to you during the UX research stage. These elements can make or break your design and your connection with your target audience; this can cost you money, time, and even your reputation.
This doesn't mean you should skimp on your user experience, be sure to do your user research and test your product or digital product before you get to the official prototype testing stage.
At that stage, be sure your visual elements create a strong identity and captivate your audience. If you do both, any minor user flaws that pop up are likely to be ignored and won't lose your potential audience.
Put in the time to research and understand your target audience. Create strong visuals based on that user research and implement those visuals with basic UI principles in mind.