Since FB is getting stricter than ever, i recommend you to use personal account. And here's why, let me show you what are the advantages and disadvantages.
1. BM account:
Advantages:
- It costs less to have one.
- Its currency and time zone could be changed.
Disadvantages:
- It's weaker, gets banned easier -> Make your ads less stable -> less profit you can make.
- Shows pretty bad results (compare to personal account).
2. Personal account:
Advantage(s):
- Stronger (usually an old one with spending history -> higher trust -> harder to get banned).
- It can spends a lot before getting banned (around 50k avg).
Disadvantages:
- It costs more to have one.
- Its currency and time zone can't be changed
=> I mentioned the currency and time zone, but it won't affect the CPR much. It is mostly your content affecting your ads.