I can't believe in 2019,people still think everyone in the UK is speaking received pronunciation,especially when the country is made up of England,Wales,Scotland and Northern Ireland - even England has different regions with very different accents. I don't find Scottish accents unusual,especially since the chap from AdoredTV does not actually have that strong an accent.
If you do find it hard to understand,you will have one of heck of time in the UK if you travel around a lot. Also,regarding der8auer his German accent isn't too strong,but I have met some Germans who speak English with a very strong accent.