You need not create an account to post scores; “upload to practiscore” is embedded in the app. All you need to do is have a consistent match title so your shooters know how to find scores.
An account is needed if you choose to have online match announcements, signups and such. You can allow online signups and posse selection if you want to, but be aware that there are fees involved if you allow shooters to pay online, and unless you set it up carefully they can cancel at the last minute and get refunds, yet you will still pay the transaction fees.
Our practical club uses it for sign-ups, squadding, and fee collection, and everyone but their treasurer (and our parent club treasurer for that matter) seems to like it.
For cowboy we post scores there but have seen no reason to use the other features.