One reason for the change is understandable, which was made quietly and secretly.
As mentioned, is WhatsApp
A recent Change to blue tick for voice message
to be done. The move was undeclared and was not commented on by the messenger service. In particular, WhatsApp has “switched off” the blue tick for voice messages. Before changes were made, the gray tick would always turn blue as soon as the recipient listened to them – even if the reading receipt had been deactivated. Now it is not so.
If only read receipt is active
The tick only changes color if the sender and recipient have now activated the read receipt. Otherwise they remain gray. WhatsApp has not discontinued Blue Tick, but has adapted it to a system known only from traditional chat messages.
Therefore this step is only logical. You really have to ask yourself why the resemblance lasted so long. Voice and text messaging are now at a similar level. This is also the reason for the change. This makes it clear for WhatsApp users. Because if different rules apply different functions within the messenger service, it can cause confusion.
Step was overdue
But that is over now. Only those who have activated the read receipt can now see for themselves whether the recipient has received voice message
It has already been heard, or it has aired but has not been heard yet. What’s right for text messages because the blue check mark has now (finally) also started in voice messages.