I think it depends on your ears. I'm a hobbyist and had it one year in. Some of my training partners trained way longer and their ears are fine. Luckily, my coaches had a draining kit and drained it for me. I wore this headgear for a bit after. If I feel my ears getting sore again, I'll wear it again.
I'd rather get called a pussy and save my ears and be able to wear earbuds.
It will help you not get cauliflower ear unless your head gets slammed against a mat or hit by a knee. It will primarily provide protection against your ears getting ground/rolled up while rolling.
If you already have cauliflower ear and need something to prevent it from getting worse/stopping healing the scrum cap won't be as useful since you need to really protect your ears. I recommend wrestling head gear with plastic covers. This worked nice for me:
Cliff Keen Wrestling-Protective-Headgear Cliff Keen F5 Tornado Headgear https://www.amazon.com/dp/B000KEFWUE/ref=cm_sw_r_apan_i_TQYE3WPK4G9DJF66MWAT
I just ordered these CK's since a rolling mate also wears it and they seem to be working fine for him. I will try out your suggestion if the CK's don't work out.
I also had previously got these but they kept falling off during training and my ear infection worsened after those rolls.
that is how it starts.
I wear this headgear for a week or so when my ears start to get sore
https://www.amazon.com/gp/product/B000KEFWUE/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
This is the one I used and I love it. I wore it for about 2-3 week until my ear healed.
http://www.amazon.com/gp/product/B000KEFWUE/ref=oh_details_o02_s00_i00
Try the travel pillow first. If you toss and turn to much to be able to stay put on that, find another method that works for you. Big hairclips that are to painful to lay on but will protect your piercing from pressure if you do sleep on it, stuff tennisballs in your shirt or get/make something like this or even some wrestling headgear