Just beacuse this UI/UX stuff and not the value of the product or its technological qualities matters really when the first user's opinion is formed. It is highly likely that you will gain new customer if such experience is positive. On the contrary - you may offer a great solution to client needs but if he doesn't understand instantly how to use it, he may go away and forget about it for good.

Why users delete applications? The research carried out by Appiterate revealed that in the case of as many as 42% decisions the reason is unnatractive user interface. When designing UI we always have in mind that user should fall in love in your vision "at first sight" 😉 Once this happens he will most likely become your customer.