Choose Desktop when
You want ordinary work stored locally, need offline day-to-day use, and prefer a permanent one-time licence.
Choose Web when
You want to avoid installation and use the same cloud workspace from your own supported desktop browsers. Web is not a collaboration product.
When using both editions makes sense
The products do not synchronize. You can replace one workspace with a portable backup from the other. Editing both copies independently creates divergent datasets. Active paid Web can supply Desktop update eligibility after secure linking. It does not replace or revoke Desktop ownership.