If you use the forward incremental backup then you will create a synthetic active full at a specified schedule. If you don't, then you will create a forever forward incremental backup. Obviously you can have issues when the chain gets broken through corruption or any other reason. But if you do a synthetic then you will create a full backup based on the latest full backup and the chain of incrementals after that. In terms of data, a synthetic is identical to a active full backup.
Last but not least, you can always schedule a health check (https://helpcenter.veeam.com/docs/backu ... tml?ver=95
To finally answer your question, is it reliable? Yes it is, but be aware that there is always a potential of having corruption, no matter what mode you use and never forget the 3-2-1 rule for backups so that you always have a copy to recover