Well... They are trying to look important, but they are not. They don't respect candidates and their time.
I had 6 stages:
1. Round with HR (30 minutes).
2. HackerRank Test (1 h, 50 minutes. I passed it).
3. Interview with a hiring manager (30 minutes).
4. Interview with QAs (they forgot about my interview and joined only 10 minutes after I reached out the HR).
5. Interview with a technical couch (30 minutes. the most useless stage).
6. Interview with a developer (30 minutes. I would say, this was the best part for me).
Total: 4 hours 20 minutes of my life spent for the interview process.
I had to take paid time off to attend that long interview. Despite the fact they liked me, there is no outcome for me. No offer, just a feedback: "...however given that our QE practice and agile processes are still evolving and are quite fluid, they felt someone with more in-depth mentoring/coaching experience and experience taking initiative in ambiguous situations would be a better fit at this time."
Well, in that case, you should have named the position not SDET but Agile Coach SDET. You are looking for a one-man-band.
Good companies would offer compensation for their candidates because you are literally wasting people's time. You got a resource, people who wasted 4 hours and 20 minutes of their life got nothing except nerves.
If you read this and going to attend an interview in CardinalCommerce, ask if they reduce the number of stages. Two-three stages should be enough. Otherwise, better check another place. Despite your technical skills and how awesome you are, they will choose a one-man band.