Depend on your use case, HTTPS may not give you the right guarantees. For example, if you are trying to check an online license (where the client running the current application is essentially a potential adversary), HTTPS gives you no guarantees that the license server you think you are talking to is the real license server. You could pin the certificate to work around this, but then you have to reinvent revocation and renewal of the certificate for your own application. A longer lived, application specific signature may be a better option.
In other cases, HTTPS's end-to-end encryption may not be completely desirable - for example, apt does not use HTTPS as it would interfere with simple caching proxies, and it offers no extra assurances than a verified signature does.