Answer: This is in line with the AML (Anti Money Laundering) purposes.
Spending limits are the limits you can spend every day/week/month on LiteBit.
LiteBit is a member of the Verenigde Bitcoinbedrijven Nederland (United Bitcoin companies the Netherlands) and because of AML (Anti Money Laundering) purposes, limits per verification tiers are set. This is the reason why you can trade more when you have a higher tier.
Would you like to read more information about spending limits? Click here.