As a sports official that doesn't have that kind of timing (ref keeps it on the field) I've always wondered about how soccer officials keep things consistent. I get it if a player has a shot on goal and time is out...I prefer when th clock on the field stops at say 2 mins then the table controls it with a horn. To me being consistent is the single most important thing in officiating (as well as fairness!!)
Obviously this timing technique has been used forever but I don't know that I have always thought it was a good idea. But then again...I have no experience using it. I guess...it works?
The best way I've heard it explained, 'Ref ... soccer is guided by, but not a slave to the clock. With an historical approach to timing, final whistles for halftime or full time almost never come in the midst of an attacking move, and the match official will never, ever blow for time up when a team is in the process of generating/taking a shot at goal. The clock continues to tick up to 45 or 90 minutes (or 105 & 120 in extra time in knock-out and/or Cup competitions) unabated, with no stoppages for delays like injuries, substitutions (limited as they are at levels higher than NHIAA and NCAA) and a myriad of other reasons we see the clock stopped for in many other sports. As you probably know, there are no timeouts in soccer.
The match official is basically allowed to exercise their best judgment on adding the legitimate amount of added time a/k/a "stoppage time" on top of the regularly allotted time. That added time usually takes into consideration the legitimate time lost to injuries and subs, adjusted (usually more) for less-legitimate, contrary to the spirit of fair play delaying tactics like slow restarts, feigned injuries/cramps, overlong goal celebrations, etc. And the amount of added time declared at the end of the half/full time is always described as a "minimum" amount, to give the match official added flexibility to guard against continuing stalling tactics. Having a firm clock or buzzer approach isn't going to do anything to lessen chronic stalling, etc.
Soccer has always been a game where continuous action and limited stoppages are seen by itself and its fans as its virtues. Playing on a huge pitch (usually 115 yards long by 75 yards wide (UNH plays to the full 120 yards marked at the end line of the football grid) with 22 players, 20 of which are expected to be moving constantly in 45+ minute segments, probably does lead to tolerance to some degree of the exaggeration of injuries, if only to provide the players with a momentary respite(s).
Traditional soccer fans don't really like the open substitution allowed at NHIAA and NCAA levels, mostly because it breaks up the flow of play. Most of the criticism that VAR (video replay) has come under has been for similar reasons. Casual observers of the game tend to (overly?) fixate on simulation and clock-related issues. My own take is, if VAR was used only for obvious errors, all-of-the-ball-over-all-of-the-line, and simulation - and not on whether an attacker was 2 cm. offsides, I'd be good. But I'm veering off course now ... so hard stop, Happy Thanksgiving Day to all!!!