Now, do not take it the wrong way, but it seems that your question is based on some wrong ideas:
- " you can program in less lines of code than in the normal way "
you can program in less lines of code than in the normal way
In fact, unless you are using all the functions available in the library, using a library you will be processing code that you will not use later. That's why it's just a false idea of saving.
Moreover, you may find that you are doing more operations than you think / expected (especially with old versions of jQuery). This is because jQuery will perform additional operations to ensure that the commands will be compatible with different browsers and platforms (something that may not matter in your particular case, but that does matter to jQuery).