You open your app. All your channels are gone. The playlist URL is dead. You have to request a new one.
This happens when resellers use unstable URL generation. Some regenerate URLs weekly. Some do it randomly. Some do it when they're angry at their server provider.
A professional British iptv reseller uses stable, permanent URLs. You set it up once. Never think about it again.
The British iptv service I use gave me a URL 14 months ago. Same URL today. Never changed. Never broken.
A chaotic IPTV reseller UK will give you a new URL every few weeks. You'll be constantly updating apps on all your devices. That's not a feature. That's incompetence.
Ask before you buy. "How often do you change playlist URLs?" The right answer is "almost never" or "only if absolutely necessary."
Stability matters. You shouldn't have to be a technician to watch TV.