I agree that excel cannot match online compiler, but perhaps excel can be used for uploading questions, options, logic etc just like translations. Yes, similar to ODK or SurveyCTO but the format can be specific to Survey Solutions. The reasons for wanting this feature has to do with efficiency of form development as follows.
(1) Speed of questionnaire development: Converting a typical paper-based questionnaire into an Excel based template (similar to OSK) is faster because we can write a VBA macro and/or use features such as filter, pivots, transpose etc. Also, easier to create a excel based questionnaire by culling from different past surveys. While Survey Solutions has ability to copy earlier surveys, they have to be in the Survey Solution system in the first place. Similarly, if we already have old questions in ODK format, typing all of these again in Survey Solutions web-platform will be hugely time consuming, but it will be easier to change syntax, column heading etc manipulation in excel and upload that form to Survey Solutions.
Also, easier to copy-paste logic/validation rules and error messages in one go for multiple questions. For example, we can write concatenate+ string formulae in excel to create ‘customized’ error messages as per question number, min-max range given etc. Changing variable names is also easier and we can do find-replace by specific columns (such as in ODK, if need to only change constraint and relevance column when a variable name is changed). In Survey Solutions, copy-pasting into the web-form takes a much longer time comparatively.
(2) Ease of review and revisions: Researchers are much used to giving comments in different Excel columns (or in word). Better still, any changes in wording, logic, error message, etc. can be just done by the researchers (at least for straightforward ones) during review instead of writing it down and then asking a ‘designer’ to do the changes in Survey Solutions web-app later.
(3) Ability to develop/revise questionnaire when off-line: We often need to make corrections in the field with limited / no internet or while travelling in plane/train. Speed/time is of great essence in small scale and low budget surveys.
(4) Better ability for multiple people to work real time (when internet is fast enough): Excel files on Share-point can be worked in parallel whereas Survey Solutions requires one person working on one section at a time (but multiple people can work on different sections). Also, work can be better divided between different team members – one only write question and options, one to check logic, one to check translations at the same time.