Game Assets even simple low-poly assets, take hours to produce. So the last thing you want is to create a bunch of assets, only to never use them in the final build.
This can happen easier than you think considering the complexity of the game design. Finding the “fun” takes a while and if we had to create art assets custom-made to get a prototype done we’d be chucking away days of work every attempt.
The smaller the team, the more importance there is on ensuring nothing is going to waste. So to avoid waste, we prototype early and use prototype game assets everywhere. Be the assets just small cubes and capsules, or free model packs and animations to go a little further.
Prototype Art Favors Design-First Focus
Going with only prototype art or janky-at-best assets from model packs is also extremely helpful for rapid iterative game design.
Instead of trying to get every asset into the game engine perfectly, which can be a full job title at times, we can just test the gameplay instantly with “good enough” art. If the base gameplay is fun with janky assets, you know you are in a good spot as you can only improve it with good art direction.
Even just using a simple free shader and place-holder models with animations off Mixamo you can get something playable in a day like the above prototype.
Even When Your Art-First, You Prototype First
Now there are times when art should be a bigger focus, maybe even the focus, but this mostly depends on the team. There are dozens of cases where a game succeded commercially off art alone even though the base gameplay wasn’t all put together.
But even then, those art-focused teams have their programmers working with prototype art and model kits the first few weeks while the art team creates those base assets.