3+0 is a lot more unforgiving. The interesting thing is that this impacts not just how players manage their time (as you mostly looked at here), but also the decisions they make during the game.
For instance, say white is winning due to having an attack going against the black king, but has little time on the clock. Their opponent gives them a chance to liquidate into a winning-technical endgame. In 3+2, they will most likely choose to liquidate because the position will be more straightforward to convert, but in 3+0 the same player would probably keep the attack going in hopes of shortening the game.
I also think that players are more willing to play unorthodox/dubious openings in 3+0 because it might provoke their opponent to spend more time if they want to punish it better.
For instance, say white is winning due to having an attack going against the black king, but has little time on the clock. Their opponent gives them a chance to liquidate into a winning-technical endgame. In 3+2, they will most likely choose to liquidate because the position will be more straightforward to convert, but in 3+0 the same player would probably keep the attack going in hopes of shortening the game.
I also think that players are more willing to play unorthodox/dubious openings in 3+0 because it might provoke their opponent to spend more time if they want to punish it better.