I'm always wary of the distinction between "practicing to failure" and "practicing to fail." That is, if you try and fail too often, you may be training your body and mind to "know" that you can't succeed at that task (i.e., you're "practicing to fail").
For example, I spent yesterday "sessioning" some tricky features on my local MTB trails. Some I cleaned after a try or two and I felt ten feet tall. A couple I just knew I wasn't going to get that day (steep, techy uphill rock climbs), so I moved on after three all-out attempts. I think it's important to make sure that your attempts are intentional and that you're getting good feedback on what you're doing right/wrong. Gritting your teeth and taking another run at a challenge can be awesome, but it can also backfire if it's all you do. You can build muscle memory for bad form if you're not careful.
I hate the word "grit," but it's because it's so misused and problematic in education. (Perseverance was a perfectly good word; why do we have to use of-the-moment jargon?) A LOT of people in education are starting to point out that talking about "grit" can be harmful and grossly unfair to kids who have to attend underperforming, unsafe, bad schools, because it makes it seem as though the kids are responsible for their fates on the same level as their more affluent peers. Ok, sorry, I went on a "Rangent" there, which is what I call a ranty tangent. Sorry. I know the article here uses grit in a very particular and perhaps relevant and meaningful way.