I don't know if I want to call it good SEO practice for local SEO companies offering their services and promoting it by hiring a link building team to make spammy comments or to the least build backlinks using link builders that do not know the value of the comment itself leaving unnatural generic words behind their company's name. For me it's not a good practice. This might add more damage than of use in the long run.
Take for example this SEO services company url - http://www.myoptimind.com/seo-services.html. People behind this company (might just be) have been boggling my SEO blog for quite some time now trying to get relevant links from my blog via spammy and robot-sounding generic comments of praise. I'm not sure if the people behind the comments are actually from the company itself but I were the owner I'd go check what my link builders are doing. It's really easy to find out if they are doing it by searching for their links, Where they come from, there must be more useless comments hanging under their company's name.
Honestly, if you offer services related to SEO, you don't send just someone without the right knowlege to make comments and get links for your company website without checking or at least giving a guide on how to do it for you.
Remember that possible clients will always go check your company profile and if in case they see what you do to get links to your website, they might just see the type of blog commenting your link building team is doing and might decide not to take your services instead. In the long run, you are actually building a profile where you are trying to dig your own company's death in the industry of SEO.
I have done the same mistake before and I must admit back then, I am not yet knowlegeable at how to make a good link without repeating your comment on and on and on. I made the mistake that I cannot take back so I just wish you guys who want to leave a comment to my blog, be careful. Make a good comment, a relevant one as much as possible and not just some fake praises. Believe me, it's not worth it. I hope the owner of this local SEO company wakes up and try to teach their link builders to do things right. There is no turning back once a comment is posted under a company's name so make sure it is your best.