Replacing Cave's Beach link with Lake would weaken the "water loop", a situation where players get continually routed back to Beach, leading to frustration. Lake is a crossroads biome that connects to much of the rest of the game, while still connecting to Beach, making it not a drastic detour.
Infernal Vulpix simulated a hypothetical 10k wave endless run for me to see the difference this change would have on biome frequencies. Apologies for the broken formatting from me copying this from Discord:
Odds Alt
Abyss 1.98% 2.40%
Badlands 3.57% 3.46%
Beach 6.30% 4.06%
Cave 5.87% 5.91%
Construction Site 3.90% 4.83%
Desert 1.70% 1.70%
Dojo 2.05% 2.58%
Factory 2.03% 2.57%
Fairy Cave 0.86% 0.59%
Forest 5.79% 5.64%
Grass 2.12% 2.48%
Graveyard 2.03% 2.39%
Ice Cave 4.00% 2.68%
Island 0.79% 0.53%
Jungle 2.80% 2.72%
Laboratory 0.13% 0.13%
Lake 3.37% 6.26%
Meadow 2.93% 2.74%
Metropolis 2.33% 2.55%
Mountain 2.86% 2.40%
Plains 5.96% 6.94%
Power Plant 2.06% 2.63%
Ruins 2.51% 2.59%
Sea 6.16% 4.07%
Seabed 2.90% 2.04%
Slum 2.58% 2.67%
Snowy Forest 3.79% 2.60%
Space 0.37% 0.41%
Swamp 3.79% 4.64%
Tall Grass 4.18% 4.73%
Temple 2.98% 3.06%
Town 0.00% 0.00%
Volcano 2.58% 2.29%
Wasteland 0.72% 0.72%
End 2.00% 2.00%
aeeebcbf38