What Venus does in a chart
Venus is the part of the chart that answers one question:What do I find beautiful, and how do I show affection? It describes love style — not events, and not outcomes.
What Pisces does to it
Pisces is a water sign, so it moves on feeling and atmosphere. It is also mutable, which means it adapts things. Put those together with Venus and you get loves without edges — porous, imaginative, merging, applied specifically to love style.
Pisces is ruled by Neptune, so this placement tends to be coloured by imagination and idealism as well.
The useful version
Placements are not verdicts. This one describes a default setting, not a limit — the things listed above are what you do when you are not thinking about it, which is exactly why noticing them is worth something.