Most of those accounts are newbies. What are the benefits of hacking newbies?

In your example above seems it is own by one owner, I think he is checking his accounts. Look at the pattern of 3 numbers after the word and the "worth" word added at the end. It is not coincidence.

Micro333
Trance555
FictionWobbles333
MoodFool333
BlackRunner111

twadsworth
 jhallsworth

All Feb 19 accounts (shown here) "reactivated" within 25 minutes.
(there is a shed load of other feb 19 "reactivations" elsewhere, look at u=2000 - 2020 @11.00am, or u=3000 onward @11.30am, or u=4000 onward @11.45am, or u=7000 onward @ 12.00pm, or u=8000 onward @1.15pm for example, a clear timeline pattern) - edited for more clarity.

It's possible that someone got their hands on the old hacked database from May 2015 and decided to actually attempt to get into accounts with info that they gathered from that database.

Another possibility is that some site Bitcoin related was hacked and people got their hands on their databases and are checking to see if there are reused passwords to get into bitcointalk accounts. For example, recently a database dump from 2014 of btc-e's database reached HaveIBeenPwned so it is likely that that database was floating around publicly for a bit of time beforehand and is still available. So people might be using that to match accounts on btc-e to accounts on the forum and then trying passwords to see if there is any reuse.

Unfortunately the forum can't really do much. If the admins lock accounts which have not changed their passwords and then send password reset emails to all of those accounts, a lot of people will be locked out because emails aren't validated and a lot are either invalid, or just point back to bitcointalk.