I agree that many
are avoiding wireless terminals for "customer experience" and similar reasons, but at the same time, I'm not sure there are/were all that many options available for the restaurants that want(ed) to use them. After all, a lot of regular stores could have gotten EMV right at the October 2015 deadline had they thrown out all of their previous POS integration work and used standalone terminals, but didn't do so for obvious reasons.
(BTW, for an example of how much of a hassle non-integration can be,
here's what happens for a restaurant to handle a Grubhub et al order:
And for many restaurants, getting app orders is more labor-intensive than taking orders by phone, if the apps aren’t directly integrated into their point-of-sale systems: First, someone must “translate” the order into the restaurant’s computers, then a manager must void the transaction to reconcile the books because the revenue doesn’t show up until later (and with the app’s commission taken out) — and then the books must be reconciled again to account for the food inventory.
Anyway, if it's a choice between a wireless terminal that causes a bunch of additional work to reconcile the payment and a non-wireless one that the POS vendor added an integration for, I'm not surprised that many chose the latter.)