Definitely. Updates are important, especially those that fix security vulnerabilities.
We do so much with our phones these days - they are single-device access to our online accounts and personal identity (Singpass, 2FA, etc), credit cards (payment systems), banking tokens (banking apps now use the phone as second authenticators), along with other transactions and online day to day activities. A bug that compromises any of those can have consequences.
It's why it makes no sense to use jailbroken phones or 3rd party firmware now, especially since the more secure of these apps check against the integrity of the phone before allowing run - for a good reason.
I won't buy a phone unless it has 1) at least 2 years of security updates guaranteed, and 2) back-end security at the OS-manufacturer level like Google Play Services for Android. Also, I am wary about custom skins for Android now, since some are better than others. Samsung's OneUI is still fairly decent and cohesive, and the Koreans do care about security enough as a culture.
Perhaps some don't care - there's always this "aiyah i'm not so important that anyone would hack me" complacency. Singaporeans in general do not take security seriously - just look at all the data leaks in recent months: Singtel, vHive, Starhub, etc... Eventually when it becomes a real problem for users, it would be too late.