Gomez had no track record nor much in the way of stuff, from what I recall. Workman has both, but not elite stuff, like Hector he has one great pitch when it's on, and a passable second pitch that works in conjunction with it. But he wasn't having a good year when we got him. He was a solid reliever from 2017-2018 and very good in 2019 while also closing for a last-place team. He's more like Tommy Hunter than Brad Lidge (but both of those players have had some disaster seasons in their careers, it just happens).
I think the bullpen is still the least important - and the closer the most overrated - part of any good team, but that does change in the playoffs, and perhaps also in such a short season (though, conversely, it's really hard to miss the playoffs and seeding doesn't matter that much). The thing is when it does matter that much, it also really is a matter of luck, or one inning not going your way (i.e. Jonathan Broxton was not a bad pitcher. Neither is Will Harris).
Girardi seems pretty committed to roles as a way to help the bullpen get on track, but a lot of times, if your best reliever is a set-up man rather than a closer, he's the one getting the most important outs anyway. Both because getting 7th and 8th inning outs actually do matter just as much (possibly more) and because of the opposing line-up. Last night that was only partially the case - Phelps faced the 1-2-3 hitters - but for Workman, having gotten the 4-5 hitters out, he had some margin for error needing just one out from the bottom of the line-up. It should have been Holt, but he still got it done. And sometimes you are going to walk guys as part of A) getting strikeouts and B) not giving up home runs.
I'd be happy to see reliever match-ups 7-9 but if Phelps keeps pitching that well I'm sure people will call for him being the closer. And then we'll probably notice his flaws too.