EDIT: I guess this was, indeed, a hot take.
TL;DR: I feel like eternal formats provide a better wildcard value for players without much to spend, but new players are rarely pushed in this direction because of a perceived cost-barrier and prohibitive power level. I personally see Standard as the format with a high barrier to entry in the form of wildcards. Much more so than Historic or Pioneer.
I see a lot of newer players come into the game and post here asking which standard deck they should craft now that they've earned up a small pool of wildcards, and it's always sort of baffling to me that this is the default constructed choice.
Maybe it's personal preference, but the rotation of Standard has never appealed to me. When I first started playing MTG ~10 years ago I skipped Standard and went straight into Modern. I was in a financial position to be able to do so, and at the time, that was the main barrier to Modern - older cards that haven't been reprinted, but are staples of the format and ergo expensive. I remember when Scalding Tarns broke $100 a pop!
In this context, recommending Standard makes total sense. The dollar value of a standard deck is a fraction of a modern deck, so it's more friendly to newcomers looking to buy in. However, on Arena this isn't how the economy works - a Timeless deck using 10 rares has the same purchase cost as a Standard deck using 10 rares. 10 rare Wildcards.
But then we get into the value of each Wildcard spent, and how long those cards will remain useful to you. Standard decks still require tens of rares and mythics, but they're seldom strong enough to become Historic staples and so end up collecting digital dust in your collection until they're potentially reprinted into the rotation.
I get it if you play a lot of limited, and ergo complete or near-complete entire standard sets, allowing you to build meta decks for free, but most new players can't pull that off and never go infinite with their gems. They're collecting wildcards and looking for a deck they can get good with over time.
New players are also typically FTP, so building a deck can take weeks or months to gather the resources for. This is often the argument used in favor of Standard, as eternal formats can be more wildcard intensive and include cards not printed into draft sets, but if you don't already have that standard collection from chaining drafts, the wildcard costs are similar. Plus, every wildcard investment in Historic/Pioneer/Timeless is more likely to remain relevant - especially lands.
Mono G Landfall in Standard costs over 30 rare wildcards for the maindeck alone. Jeskai Revelation is 34 rares and 8 mythics for the maindeck.
Historic Izzet Phoenix, a top-performing deck in the format, can be built with 8 mythic and ~15 rares, and it's an archetype that has existed for as long as Arclight Phoenix itself has been around. Barring bans, you'll likely be able to play that deck for years to come. My fiancee built it using budget lands for a few slots in the short-term with nothing but the wildcards you get from the free packs in your inbox on a new account + the $4.99 welcome bundle.
So why is this seen as the best way for new players to get into constructed play? Is it simply because Standard has always been seen as the, well, "standard format"? To me, Standard seems more like a format you play competitively, ignoring any idea of a budget, and chasing the meta with your wildcards every rotation. It's the format that limited players, streamers, and pros can afford to mess around in because they have entire sets completed and a bank of wildcards. It's also the format with the most tournament event representation, so it will naturally attract the best players looking to qualify for the next Arena Championship or what have you.
It's not much more "casual" than any other constructed format as far as gameplay or power level, but punishes casual players more severely by making them spend wildcards every rotation if they want to actually win games.
