Hello, @Wienart!!
SteemAuto is a tool on the Steem blockchain. Its function is to automate some behaviors of your votes, for example, voting automatically the same posts as other user, this is known as following a curation trail, you can also automate your votes to vote on some user you like, and set a fanbase to vote on the posts those users publish. You can set a percent of your vote for each of those functions. The benefit is only to use your steem power and earn curation rewards, if you are not used to up vote manually on a daily basis. Also, you help those curation trails you are subscribed in the SteemAuto app to reward the post they curate.

Hope this helps!