Bump bots are quite good in bumping your thread at the right time for clients to see your services and opt for them. As far as these bots comply under the rules of this forum it is good to proceed further with a newbie account of your's acting as a bump bot.
Similarly if the announcer doesn't have enough interest in the forum to become an active member, why should we consider his product.
No, activities shouldn't be considered while opting a service. A newbie can also offer a good legitimate and a far better service than a legendary guy. If you consider the collectibles section for instance, newbies and Jr members are one among the trusted people and they do announce their own product and people buy them.
This forum is not just for discussing things about cryptocurrency. Some People come here only for offering their services and buying things. They might have lower activity but can offer good services.
If the thread doesn't get any active replies or comments, then it is unlikely to be of benefit to the members here, so it should be allowed to drop, and leave space for better quality products.
Probably people hiring such services might reach out to the OP via PM by going through their portfolio and there is no need for them to post a public reply in their thread.