You should get a Level advance if you're looking to invest in growing your business and expect that investment to translate into increased future earnings.
Level charges a fixed fee, which is included in the total amount you'll repay in addition to the advance. That fixed fee is the only fee that Level charges - so you'll always know exactly how much you'll repay.
A Level Advance only makes sense if you expect the return on investment to exceed Level's fixed fee.
If by using the Level Advance to invest in making more money than the cost of the fixed fee, then you've made more money in the long term! If not, then you've paid the fee without increasing your earnings.