Honestly, even with that limit it is rare for me to take out my physical card. If I'm alone at a restaurant, or splitting a bill, it's under that, and many restaurants' readers are starting to accept tap now. I tend to do small batches of grocery shopping more frequently, so that's usually under 100. Big ticket electronics/computer purchases tend to be online for me. At this point I take out my credit card maybe 2 or 3 times a month, for the occasional large grocery shopping run or group restaurant dinner that I'm covering, and the ultra-rare establishment that doesn't accept tap, and that's it. It's even better for me since I use my apple watch to pay so I don't have to take my phone out.
But yes, you do have to keep the cards. That said, if driver's licenses and health cards were allowed to be kept digitally here, and if a few holdout stores started offering digital copies of their cards (looking at you, Costco and Ikea), plus Presto, all I would realistically need to carry physically would be one credit card (no debit card if ATMs were to start accepting apple pay like in the US) for large purchases and $40 in emergency cash, in addition to my phone and my house/car keys. I would probably switch to one of those phone cases with card slots at that point for the 1 card and 2x$20 bills. And as for keys, the new Tesla Model 3 is primarily unlocked and started with a phone, it's only a matter of time before car keys disappear, and there are tons of home smart locks on the market now.
As for the frequent argument against making Presto, and all this other stuff, go on the phone because the battery might run out, I'm an adult and am capable of taking responsibility for myself. I have never once had my cell phone run out of battery since my first one in about 2006. I've had a flip phone, then iPhone 3G, 4, 4S, 5, 6+, 6S+, and 8+, and my battery has never gone below 50% on any of them with one exception, the 6S+ which ended up with a bad charging port so when I plugged it in at night one day I woke up and didn't notice it hadn't charged, but wireless charging has abated that concern and I now carry a phone charger with me for emergencies during any extended outing. And my apple watch, which is what I use for apple pay and what I would use for Presto, has never gone under 50% since getting it in 2015.