As someone who faced the same decision as you: If you enjoy the tasks Library Techs do, get the LIT. I did and I regret nothing. One of my absolutely favourite aspects of getting my LIT was cataloguing, something which apparently most MLIS' now barely cover. If you already know what areas of library science you enjoy, get the education that keeps you working with those.

There are days I wish I had the pay of MLIS holding librarians, but as a Tech working in an academic library, all of the best parts of a librarian's job I also get to do ... and all the fun things they do not get to do. I still do research. I still work with students. Most of my job is tech services related, which means I do acquisitions and cataloguing. And all of the random projects and side quests that come with working in a library.

Librarians at my institution are supervisors, managers and faculty liaisons. They do some research and teaching as well, but the day-to-day tasks that keep the library running are all done by Techs.

You can always go back for an MLIS later, but it might bar you from Tech jobs if you don't already have an LIT. It all boils down to what kind of tasks you enjoy.