Advantages:

It has a lower cost and a more straightforward design.
It provides maximum exposure to the pay zone, increasing the productivity index and the performance of the well.
Lower pressure losses due to larger diameter conduit
Causes less formation damage: Since the reservoir section is drilled using non-damaging drilling fluid and is not cemented or perforated, less formation damage occurs. Less damage keeps the reservoir close to its original conditions, not requiring severe stimulation efforts.
The well can be deepened in the future if required
Completion can be modified in the future by running a liner if required

Disadvantages:

There is a higher risk of hole collapse: Since there is no mud cake or cemented casing to support, less consolidated rock could collapse during production.
There is no control over sand production: Small sand production can be managed through not-so-expensive means, but significant sand production could require a major workover operation.
There is limited zonal isolation: If multiple open zones contain different fluids, the production cannot be easily controlled.
It is difficult to carry out selective zonal stimulation: Since there is limited zonal isolation, stimulation fluid could go to the high permeability zone, leaving the lower permeability zone improperly stimulated.