In general, a player should always go for max damage whenever a launcher is landed. However, every character has moves that, despite knocking down, these moves won't allow for a combo.
When the opponent is juggled in mid-air, the more hits landed result in the opponent being refloated to lesser heights. This is called Juggle Decay. Eventually the opponent will not be able to be refloated.
Attacks that combo while the opponent is standing do not add to Juggle Decay.
Some characters can use P or 2P to pick up the opponent if they decide not to tech, and still get a good combo. A good opponent won't allow for this, and will tech to avoid eating unnecessary damage.
In some cases, if the opponent does tech, the player will still have advantage even after the P/2P whiffs.
If the player notices the opponent is teching from the knockdown often, they can start using meaty mixups.
Some characters have access to strings that can OTG. Some of these strings can double as a mixup to deal with an opponent teching too.
If you make your opponent afraid of your meaties, mixing them with OTGs will make any VF character much more deadly.