You wouldn't leave a hole in your shop's roof. Why are you leaving a bug on your checkout page?
In Poland there's still a "once and done" mentality about websites. A company hires someone for 2000 zł, the site gets made, then for five years nobody touches it — until one day it breaks. SSL expires, forms stop sending emails, Google drops the site from results for being "unsafe." Suddenly the "cheap site" has cost 50,000 zł in lost customers.
A site without maintenance is a car without service. It drives — until it doesn't. And when it doesn't, it's always the worst moment.
Hosting is a 21st-century utility. Electricity, water, internet — and now hosting. Four things a modern business can't run without.