Stadia is (for now) a good solution if:
Stadia (for now) is not a good solution if you are looking for:
Depends if any of the available titles are of interest to you. If there isn't much that really grabs your attention, and if you are able to play those few titles on a PC then that might be the better choice for now. You might also be able to get a much better price for those games elsewhere than on Stadia.
However, if there are enough titles that you think that you would purchase, or if there are titles in the Pro lineup that are of interest and you're prepared to keep your Pro subscription running, coupled with say planning to play those games on a TV and not just on a Chrome browser, then I would say possibly Yes.
Just be aware that Stadia is still evolving, not everything is great and working perfectly all the time, it's still feels like stuff is very much in test sometimes. Game choice isn't that great at the moment IMHO, pricing is pretty awful too if I'm honest, and discounts are only for a few titles and short lived as well.
But, I guess a lot of the early adopters are kinda prepared to be in it for the longer haul with the understanding that it is a work in progress. Of course, some of the early adopters also expected a lot more than was actually given either through poor communications from Google/Stadia/Phil, or just incorrect expectations (Stadia is not a Netflix for games).
Ultimately, it depends on what are the drivers for your decision to buy into Stadia. If you could share more information about what titles that interest you that are available now and in 2020 then you can at least see if that is a good start to help make a decision, before looking at the cost of those games on Stadia vs Steam if that is even an option for you.