What are the disadvantages of cranking with a spinning reel?

I don't think there are any! It comes down to what you like to fish with. One thing is, you want a slow speed reel like a 4-7-1 and I think most baitcasters are high speed but I am sure someone makes a slow baitcaster.

What are the disadvantages of cranking with a spinning reel?

The speed of the reel, most of them have a high IPT.

What are the disadvantages of cranking with a spinning reel?

The speed of the reel, most of them have a high IPT.

Raul, is it fair to say that that's only a disadvantage if the angler wants a slow-moving bait? And a disadvantage with baitcasters with low IPT if the angler wants a fast retrieve?

I use spinning equipment and fish cranks a lot and there's no problem at all that I can see.

None ! (except line twist)

I use spinning gear for crancks under 1/4oz, BC for heavyer...

For me it's not that Spinning reels can't handle cranks, but I just hate using them for that type of bait. I prefer baitcasting reels for crankbaits, spinnerbaits, and buzzbaits.

What are the disadvantages of cranking with a spinning reel?

The speed of the reel, most of them have a high IPT.

Raul, is it fair to say that that's only a disadvantage if the angler wants a slow-moving bait? And a disadvantage with baitcasters with low IPT if the angler wants a fast retrieve?

I use spinning equipment and fish cranks a lot and there's no problem at all that I can see.

Nope, the disadvantage comes with deep and extra deep divers, they just don 't like being reeled in at high speed, some offer such high resistance that it feels like you are reeling in a bucket, others when retrieved at high speeds roll on their side and don 't work at all.

Thanks for the input everyone. Most of my cranks are shallow runners. Only have one deep crank.

My reels are all 5.2:1 or something like that.

IPT are around 26-28 in my spinning reels I believe. Nothing over 30 for sure.

you should be OK.

What power and action rod do you plan to use for this task ?

Since I'm just learning cranks I'm using my old Bass Pro Graphite 6'6" medium power and action rod.

I also have a 7 foot medium fast action rod as well that I'm going to string up with 10 lb mono.

If I have some success this year than I'm going to get a better rod.

Go with the BPS Graphite first. If keep "unbuttoning" themselves while reeling them in, you need a softer action rod. I use the BPS Graphite 6-6 MH as my spinnerbait rod and it works great.

Let us know how it works out !

I don't think there is any disadvantage to them but you might be able to cast some lighter baits a little easir.  

For me I like using a Quantum Energy Pti-a 20 for cranks.  It has a 24in IPT as compare to my Shimano Sustain 2500 which 33in IPT.