If that Voice Memos application is a "core one" for Mojave (like Apple's Mail program and Safari are for any Mac OS), then it is wise not to remove it. I know I have tried to remove some applications that come with the Mac OS, and it caused me issues (also I believe I have seen it stated that such "core" applications are not to be removed.
I rarely, if ever, use Safari, and never use Apple's Mail program, But I can't get rid of them. Similarly with Spotlight and Time Machine. I never use them, as I use EasyFind for my searches, and SuperDuper! for my backups.