It's not worth it selling out and using rental, you will literally just lose money. Unless you want to try different decks every week.
It will probably take a lot of time until arena end up having all the cards pool. And I don't think they will shut down mtgo until there. They know there are A LOT of people that play different formats than standard and limited that would rather play anything else than waste time playing standard. I don't think arena needs the player base from mtgo. And honestly I think the 'profit per capita' of mtgo is bigger than arena's.
Is buying $40 digital “Okos” whenever a new set comes out - only to see its value go to practically nothing in a short while - wasting money?
The trend for all mtgo cards is down. That’s just a fact. Mox Emerald is what, $2? It used to be over $100. Pernicious Deed used to be over $100, now it’s a couple cents. There’s no investment here, you’re giving money away no matter what.
Yeah, but the rental service costs about 13% of the rented cards value per month (taking what I saw from cardhoarder). 15% if you consider buying always from one bot is expensive. If you want to play for 7 months you are way better off not selling out to rent.
If you’re going to play the same DPS deck for 6 months, then it’s more worth it to just own the cards sure.
But if you want to play a different deck every week, experiment with new cards or ideas then
Manatraders is only $35 a month flat for renting up to $350 value of cards (which all Vintage decks tend to be under) and you have access to any new printings. You essentially have a boundless collection for $35 a month and don’t have to worry about the program being deleted.
I will echo what @desolutionist says. Renting is gas. I would never get to try all sorts of things in this format without my rental sub.
I will also put forth Cardhoarder as well as another rental service. They do have a bit of a wait list (because the service is so popular) but they have stellar service and I feel they're more flexible to work with than Manatraders is (I've heard plenty of bad PR stuff about Manatraders, tbh).
The only caveat is that CH is a weekly fee but in the long run you are paying only for what you think you need and can pause/change as needed (say you need to pause for a week, you can do this) and also paying for a solid customer support experience as well.