Table Field Default to ZLS

Is it a bad idea to set all fields, where possible, in a table to default to a ZLS by placing "" in the field's default value when creating a table?  I have been working with databases since dBaseII in the '80s and my applications are for in-house use, never to be sold, and not huge file sizes, over a local domain, not clout based, no SQL server.  And, I don't want to create complicated VBA to create an SQL that will ignore Nulls, I get by with some VBA but I'm no expert.  When I filter by form (sometimes multiple field filters) and I place text in the "filter" text box & requery/refresh in an "OnExit" event, I do not want records with null values for that field to show in the dataset.

My last application included filter-by-form fields that proved to be very difficult due to Null values in the table fields.  I was pulling my hair out trying to not show null values for a particular filter field.  I don't use the "Form Filter" in the form itself, I find this to be troubling and unstable.  I use criteria in the underlying query matched to filter fields in the form header.

What I also find troubling is that fact that when I have a record field with text and I delete all text within the field the value is a ZLS, not Null.

Can anyone give me a valid reason why I shouldn't completely eliminate Null values and force ZLS by default in my table(s) based on above?

Help is appreciated.
Charlie