Yes, some apps (like banking ones) require some Google dependecies you can only get by installing gAPPS. Depending on your use-case, you actually can skip them, if you don’t need them (for whatever reason): just avoid flashing the package and you’ll get a LineageOS completely devoid of Google.

Choose carefully, as you can’t flash them later without doing a data format (which means losing everything you have on your phone, except for media such as music and photos, maybe, I haven’t flashed in a long time, so I could be wrong. Check an official LineageOS install guide for whatever other device, steps are almost always the same)