Meh, depends. For their case, for an internal CLI tool that will get used interactively on development environments, it's fine, the cost of switching is not very heavy. At worst they're postponing the work of deploying on other package managers, and devs will have to run 2-3 commands to remove the npm package, configure whatever next place it gets deployed to and install the new executable.
Sure, should have s/much stickier/sticker/. I'm not going to comment on whether the tradeoffs are worth it, I just thought the hammer analogy doesn't work due to material differences in how you switch between hammers vs package managers.
Not a big deal at all.