I have been carrying daily; 2015 (15") MacBook Pro, 12.9" (2015) iPad Pro, 9.7" iPad Pro and iPhone 7+ - not 'because I can' - but because I've switched from iMacs, to MacBook Pros, and with the advent of the 12.9" Pro and its size, speed and memory - we've replaced the computers with iPads almost entirely
I run and have for almost 30 years, a mobile entertainment company, focusing on weddings, parties and corporate events/holiday parties.
We used the iMacs for a long time pre-thin build (2011s) w/1TB internal drives able to host all of the media internally and w/redundant external HDDs, they were perfect - the MacBook Pros took a while to hit the TB internal mark and I was hooked on the SSDs Appl was beginning to use - still, external drives were the optimal solution but the MBPs are expensive - easily broken/busted in a 'party' atmosphere... whether by spilled drinks, spilled laptop or just stupid decisions, the iPad was certainly the 'way to go' - yet still too slow and without the internal storage necessary to host the media
ITunes Match was increased a couple years back to 100,000 songs, iPads were increased to 2/4GB RAM & local LTE speeds have exponentially increased while data prices have decreased allowing a one and a half pound (12.9") iPad to be always connected, without AC, the batteries last an entire event plus - and with USB 3 I/O (12.9" only pre-10.5"'inclusion) allowing us to use external DACs for connecting to the console/controller.
I'm definitely a 'niche' need/anomaly, but I'm sure plenty small business owners are/will or have contemplated switching to iOS. Fortunately, in my case, the audio production and love 'DJ/VJ' iOS apps are aplenty and with longevity. I have the MacBook Pro still for some of my harder workflow tasks, including video and audio editing and grading/finalizing. That said, I'm floored by the 'speed' of the new iPad Pro 10:5" (I'm waiting on the 12.9" to get here, but have had the 10.5" for a couple days) performance using iMovie, exporting 4K edits and projects is amazingly quick, twice the speed of my original iPad Pro which was still fast!
My computer bag w/MacBook and two iPads with Pencils and a Bluetooth keyboard (Magic 2) w/some other odds and ends is less than 10 pounds and made outta real leather. I rarely carry my chargers anymore ...for either MBP or iPads as their easily lasting a day - and while I've found the 12.9" models perfect in pairs for
my business, the 9.7"/10.5" perfect for my personal iPad'ing, and the laptop power there when necessary to be the best of all worlds ...as it wasn't long ago I was humping Class A A/B amp racks and speakers, halogen light racks and LPs (vinyl records) or CDs in their heavy boxes - today's AIO controllers w/USB sound cards built in with active speakers and LED lights have decreased weight by many fold! I've NO Problem schlepping a 4.5lb laptop and a pair of one pound iPads around
TL/DR; no, it's not ridiculous to carry both as they're definitely different tools for different jobs.