Some advantages of having multiple delegations are;

1. You will get multiple airdrops since many validators has their own protocol such as Angel Protocol, Orion.Money etc.
2. Lower risk because if one validator misbehave, you as a delegator will also be penalized.
3. Too much voting power in one validator is not good because it will defeat the purpose of decentralization aspect of Terra protocol.

Disadvantages that of having multiple delegations are;

1. You will lose some airdrops or airdrop amount. The less you stake, the less airdrop you will get.
2. Hard to keep track of each validator. This will also leads to your diminishing return as many validators put very low commission only for a period of time in order to attract new delegators.

Table below shows delegator addresses and how many validators that the address delegated to at least twice. There are 23550 different addresses which is around 44%.

Then from table below, we can see the delegator addresses that delegates to same validator, the validators addresses and how many times have they delegated to that same validator.

Out of 53379 addresses that had delegated so far, only 33807 had delegated at least twice which made up of 63.3%.