If someone doesn't use KakaoTalk at all, they're not exactly 'normal,' right?

I met this person recently, but no matter how many times I added their phone number, they wouldn't show up on my KakaoTalk list.

When I asked, they said they don't use KakaoTalk at all. They told me to just reach out via text or call.

I don't know what they do for a living, but if a Korean in their 30s doesn't use KakaoTalk, is it safe to assume they're definitely not a 'normal' person?