DLR is not much different from other aptitude tests or other assessment b.s.. (Though the high fail-rate at DLR of recent EX-SR candidates, has made MANY "important" people think about the overall validity!!)
DLH, LCAG,CFG,CiB and CLH (all Lufthansa "members") require the same test, because the first four are all on one seniority list, being able to switch companies/positions during their career.
To make it easier for younger CLH-FOs to possibly get into one of the four, they have to pass the DLR test, too, albeit with different age etc. requirements.
The Long-range stuff is a load of cr@ck from the dark ages, the LBA understaffed and under-funded...
Why would someone go through it?? - Maybe because they need/want a relatively "safe" pilots´ job.
It all depends on what you expect, and for how long.
The "security" of the contract, as well as the "safety" of german labor laws, do have a price (pay itself ain´t that wild), though.
But nobody´s been furloughed here for quite a while either.