Missing one call may not seem important to you, but when an ATCO is working there socks off trying desperately to get traffic information out to you and then has to repeat it several times its no joke.
On a FIS we are obliged to tell you about known traffic also working us, it is not just an alerting service.
Yes we all miss calls and as an ATCO I'm no different but for those who regularly don't listen out why bother asking for a service in first place, if all you want is the pressure setting why don't you just dial up the ATIS.