Dtyjlui

My question is about limited tournaments like draft or sealed. Can I ask for Wastes for my decks like basic lands?

No, you cannot.

From the MTG Tournament Rules:

7.2 Card Use in Limited Tournaments

Players may add an unlimited number of cards named Plains, Island, Swamp, Mountain, or Forest to their
deck and sideboard. They may not add additional snow basic land cards (e.g. Snow-Covered Forest, etc)
or Wastes basic land cards, even in formats in which they are legal.

You cannot. In the sets where they were available, you had to draft them from the packs.

In Limited events, you can play Wastes only if it's in your card pool. For Sealed Deck, that means you have to open a Wastes in order to play with it. In Booster Draft, you have to draft Wastes. Figuring out exactly how to pay those {C} costs will be a priority in this set. (But don't worry—Wastes isn't the only way.) You can't just add as many Wastes as you want while building your deck like you can with the other basic lands.

From the official tournament rules section on drafting:

Only cards from the expansions of the boosters opened (and only cards opened or drafted in that player’s pool)
may be used in a player’s deck. The following are exceptions to this rule:

Players may add an unlimited number of cards named Plains, Island,
Swamp, Mountain, or Forest to their deck and sideboard. They may not
add additional snow basic land cards (e.g. Snow-Covered Forest, etc)
or Wastes basic land cards, even in formats in which they are legal.

The link you posted to Wastes on Gatherer has the answer you seek:

In Limited events (including Sealed Deck and Booster Draft), Wastes must be in your card pool to be included in your deck. You can’t add Wastes to your card pool in the same way that you can add other basic lands.

Only cards from the expansions of the boosters opened (and only
cards opened or drafted in that player’s pool) may be used in a
player’s deck. The following are exceptions to this rule:

Players may add an unlimited number of cards named Plains, Island,
Swamp, Mountain, or Forest to their deck and sideboard. They may not
add additional snow basic land cards (e.g. Snow-Covered Forest, etc)
or Wastes basic land cards, even in formats in which they are legal.

As above answers you can't.

The example with wastes is quite simple to understand. If I wanted to run walker of the wastes in my limited deck, this would be overpowered if I had added 10 wastes to my deck, a 5 mana 10/10 is nothing to snicker at.

This is very odd as it forces to keep the basic land in the pack during draft to ensure you have a chance at picking the waste over something else if you wanted to.