That's not terribly helpful if someone is trying to decide whether to seek a job that leaves them significantly underemployed. Like, should you stock shelves at Target, or not? If you do, what do you tell people when you apply for a software job?
I think it is true that any employment is better than none when you've been unemployed for a while, but at the same time, it's hard to fake commitment to a job that doesn't use your skills, and hard to sell it to the next person. It's not "nice" even if you can fake it, even though I wouldn't ever judge someone who does what they have to.
My solution is temp agencies and/or volunteering depending on what your finances permit. That way you get some people that like you and will recommend you, and I think it's important not to overestimate how much time it takes - just a few months and you can get fantastic references without a pre-existing network.
Non-profits love volunteers that act like it's a real job, rather than flaky people and students.
Also, hospitals are used to putting volunteers to work, and if you ask, there is probably plenty to do that is administrative and not related to patients, which can be massaged into a resume for any office job. In my experience they treat volunteers almost like real job applicants, which can seem ungrateful, but also can almost be like training wheels to get a person used to employment again.
You might not think you can afford to spend time doing these things and not making a decent income, but that depends on whether just spamming hundreds of resumes will get you a good position in less time, and what kind of certainty you have.
People say "it's a numbers game" but for me, the variance and "unknown unknowns" are too big - if I'm sending out tons of resumes and not getting responses, I have no idea if the probability is very small or zero, because of some factor I'm missing.
Any time I fail three times in a row, I infer some deep analysis and change of course is needed. I'd rather identify a handful of "bricks" that are needed and assemble them one by one.
The barrier to get over is convincing people who don't know you to trust you in a long term relationship, and the solution is building that trust in steps. Realizing you need some patience, but not that much patience.
The underlying concern when hiring anybody who isn't currently employed is - is this person employable at all. So don't get distracted from that being a pre-requisite before any other qualifications are in play.