Please help me understand 2 color manabase

I've been watching e.g. [this video](https://www.youtube.com/watch?v=MDc4v7sDaQY) which talks about how to setup a 2 color mana base for commander.

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For those that do not wish to watch this video, this is the summary of what it recommends:

* 8-20 basic lands * 7 fetch lands * 7 dual lands * 2 filter lands * 1 bounce land * 4 any color lands * 6 utility lands

I've been playing a 2 color deck, with roughly an equal split of both colors in the mana costs, and I run exclusively basic and utility lands. The basic lands are also basically an even split between my two colors.

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In the +-10 games I've played, I've not had a problem with getting my two colors, most often starting the game (after potential mulligan) with lands of both colors in my opening hand (although I do occasionally mulligan if I don't get both colors). My commander is \[\[skullbriar, the walking grave\]\], so getting both colors by t2 is very important.

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Furthermore, I've also never encountered not having enough colors mana to cast any spell I'd like. I'm much more limited by the total amount of mana I have available than the colors.

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Can you help explain why sources recommend having e,g, fetch, dual, filter, bounce and any-color lands in a two color deck? I feel like the downside of having lands that come into play tapped outweighs the benefit.