Why sometimes there are multiple releases of the app daily?

Sometimes the frequent updates are necessary to fix problems for ALL users, as soon as they are detected. The app works on about 10000 device TYPES, each of them may have multiple Android versions, further modified by manufacturers, different other apps installed may interact causing problems etc. It's impossible to test myself on all of them before a release.
 
Beta test releases are often not enough to detect all such problems - about 8000 users signed up for beta-tests, of which only about 100-200 will actually update the app during the first 2-3 days after a beta release, and only some of them will submit error reports, if found. We may see any given problem, which may affect say only 2% of users, only after thousands of people updated the app and started using it. When such discovery is made, I do not want to keep the 2% users hostage and deprive them from the app usage only to please the few "frequent update haters".
 
If you really hate updates so much, you have an option in Google Play store app to disable automatic updates for any given app, including @Voice (open the app page in Google Play, press them menu button, 3 vertical dots at top right, then un-check there the "Enable auto update" box). You may then update the app manually at the time convenient to you, or keep using the old version only.