I've found that several of my internet-dependent devices can connect via ethernet and wi-fi at the same time. So, is that a good/bad idea? Or, should I choose one over the other and is a hard-wired connection always better than a wi-fi connection?

Thanks.

iMac (19,1, 3.1 GHz i5, 12.7.4, 40 Gb RAM); MacBook Air (1.8 Ghz, 8 Gb RAM, 10.14.6, 256 Gb SSD) Vodafone router and Devolo Wi-Fi Extender, Canon TS8351 printer/scanner.