If you see the reply from @Alex_Boom above, they have added a feature that fixes this for dropdowns. ComboBox appears to not have this feature but leaving Default blank and DefaultSelectedItems as  has the same effect.
FYI though, what you are attempting to do is actually what I ended up doing before the feature, via ClearCollect.
No, it is definitely a bad solution. Because the user can submit/patch that default blank value (or default "Select an Option" value for example) into the database. You can use a combobox instead, if you use the onchange attribute carefully 🙂