Why for a simple update gnome software center asks for restart but other distros don’t require to do restart it just works. is my os has this issue or it is a issue in fedora all over i am in 34 so don’t know about 33 or 35.
Updating actively running software is difficult to do, like changing a car tire while driving. Possible, using special equipment, but much easier to do when the car is stopped.
In most cases a software update’s changes will be put into play the next time loaded and the current running environment is fine. But if a dynamically loaded library or configuration file has been changed and has dependencies on other changes that may not be loaded yet, there is risk of an inconsistent environment. Best practices would be to reload and ensure the consistent environment. I suspect many of us may look at the nature of what has changed and make a guess at the need for a restart even when advised to do it.
You can do “online” updates from the command-line using
sudo dnf up. This will usually work, but multiplied by all of the hundreds of thousands of Fedora Linux systems, it’s more likely to have some problems, so reboot is the default.
It isn’t that the requirements are any different. It is just that different distros have different practices for notifications.
And some of them just accept the risk of online updates.
See dnf-needs-restarting (8) or needs-restarting (1). As @mattdm mentioned, other distros are less cautious, but then Gnome Software may be overly cautious (a good thing). After update, execute
dnf needs-restarting --reboothint # Whether reboot is required (exit code 1)