Spamming comments is frowned upon by the community.
Comment spam is currently defined by @steemcleaners as:
10 or more generic comments per day that are not in response to a question posed by the post or comment. “Thanks”, “Great Post!”, “Great Photo!”, “Good”, “Like”, “Nice”, “Wow”, “Cute”, “Follow me”, etc.
Commenting on old posts to hide self up-votes or a voting trail.
Copy/Paste comments that serve no purpose or the purpose is self promotion (including copying and pasting similar comments in rotating way).
Comments that inform the contributor that they have been up upvoted, resteemed, or flagged when the curator does not actually upvote, resteem, or flag the post.
Fishing/farming for votes by posting comments on known comment curators by using multiple accounts.
Unsolicited and off topic referral links.
Continued comment spamming may result in action from the cheetah bot.
More Info: Abuse Guide - 2017.