Vonleh couldn't even make a roster last season and played only 11 minutes the year before. He is basically the text book definition of a fringe NBA player. Should we start signing guys like Mario Hezonja as well. You know another guy that is 27 with a bunch of starts (less at 69, but still a real number). Makes no difference he hasn't been in the league for 2 years, he showed real promise once 5 years ago.
There were a lot of players reportedly available that might not have even cost Boston a draft pick to acquire. Duncan Robinson, for example, might have come with draft compensation from Miami as they were looking to remove salary and couldn't find anyone to take him. He is clearly overpaid, but he also would have fit nicely as a wing shooter off the bench.
You could pretty much have said the same thing about Gary Payton II before last season, but I don't think the Warriors regret bringing him on. (It should be noted that the Warriors are dumpster-diving for their last 2-3 roster spots as well this season, with UDFAs or former 1st round washouts likely to win a spot or two.) Miami's solely going the UDFA route to fill the last spot it seems, which has worked for them, as literally 6 of their current 14 players under contract have been UDFAs/2-ways for them in the past.
Sure, the Celtics could have done what the Clippers are doing, and filled out the roster with a bunch of guys making the MLE or more. It might work for them, but check in after they've had a bad road trip and see who's complaining about playing time/not knowing their role. (Hi, Marcus Morris - thanks for being a leader on the deep 2018-2019 team!) But they aren't, and that's fine. They're instead sorting through a bunch of players who realize this could be their last best chance to have an NBA career, who should be near the peak of the abilities, and filling out a roster of guys who will know their role. Maybe one of them completely shows out a la Payton II last year, and maybe not. If not, I will be frustrated if a move isn't made at the deadline, but there's zero reason for the Celtics to force the issue now. They return literally the most successful starting lineup, in terms of net rating, since tracking for that began. On top of that, they upgraded their #6 man, thus increasing the quality of depth at the top. Is there going to be a hole on the team? Most likely. Is it clear where that hole will be? No, not at this instant. The Celtics should fill that hole after it presents itself, and not sign up for albatross contracts like Duncan Robinson, or to a lesser extent Rudy Gay because they're available.
I don't understand how people in this thread, and not just Moranis (you don't need to reply, I just quoted you as an example) are so worked up at this point in the season. The Warriors are in a very similar boat. The Heat are in a very similar boat. The Bucks decided to go a different route and sign the corpse of Serge Ibaka, but is that any better? Would our depth feel good with someone who put up a -3.8 PER in 22 minutes in the playoffs last year? (PER isn't my favorite stat, but I didn't know it could go negative until I looked at Ibaka's playoff production). The Nets grabbed Aldridge, Millsap, and Griffin for the minimum last year offseasonn, which we all thought was patently unfair. How did that trio look?
I'd much rather have a bunch of former 1st round 26-28 year-olds taking up the back 2-3 spots of the roster. They're on completely non-guaranteed deals, so they're easy to cut bait if you need, unlike recent 1st and 2nd rounders who aren't ready but impose a long-term cap hit if you cut them and whom you're invested in developing despite also trying to compete. They've been in the league, so they know the ropes. They want minutes, like every player, but don't expect a role to be handed to them, unlike guys who've been around for a decade as starters or even stars.
I think one of the training camp invites will stick in the league for 5+ years after this season, having carved out a role in the back of the rotation for this team. I don't know which one, and I change my mind on that daily. I think the others that make the roster will be off by the end of February, and I think it's reasonably likely that the Celtics acquire a new player during training camp as another team looks to clear a roster crunch (I'm angling for Stanley Johnson from Utah).
Anyway, that's a long-winded way of saying that other title contenders also bargain shop, and have done so successfully, so it's perfectly reasonable for the Celtics to do so as well. It's neither a sign of cheapness or incompetence.